Heritage

Everyone comes from somewhere. Heritage represents this somewhere. These are skills your character plausibly learned from the people around them, even if they never actively pursued such skills themselves. Your character does not need to be a sailor by trade to know their way around a boat if they grew up in a coastal town. If your character lives in an agrarian community, they may not be a farmer themselves, but many of their close friends or family probably are, so they've likely learned a thing or two about it.
Heritage works very similarly to Backgrounds. During character creation, you select a Heritage appropriate for the community your character grew up in and gain the associated features. Many of these are defined by the economic or cultural focus of the community, but some are defined by the unique geographic elements that influence those communities which develop in them. A Heritage typically represents an entire community, but may represent a more narrow focus: a neighborhood, social circles, or the like to which a character was restricted. There is no society that consists entirely of social elites, but a character that grew up among such people, even if they were a small percentage of the population, would have a very different skill set than one who grew up among the commoners. Heritages are intentionally broad as it would be impossible to list every possible nuance possible in terms of communities.

Why Heritage?

The standard D&D Backgrounds are good for skills your character has learned from how they spent their time, but it doesn't include anything to represent the culture they grew up in. The Player's Handbook and other supplements include this in the race's features and traits, such as the Dwarven Weapon training, but it leads to two unfortunate implications.
The first is that all members of that same race share the same culture that puts value on the same things (ie EVERY Dwarf in the world comes from a single culture that values learning how to swing an axe). Personally, I find that very improbable for most settings, as there are typically many distant cities of various races. It's ridiculous to assume that two cities thousands of miles apart and in vastly different geographic and political surroundings would have the same values simply because they are inhabited by the same species. What about those people who grew up in a mixed-race city or as a minority in a culture dominated by another race? Surely those people would be influenced by the culture around them?
The second is that certain races have some innate gift for things; that they are simply born with the ability to swing an axe or shoot a bow because they evolved this way (one wonders how why this trait would evolve before such weapons were invented). The Idea that some skills and proficiencies are an inherent part of a race's physiology makes sense for certain skills such as Acrobatics, Athletics, or Perception which can be justified as due to a race having something such as more muscle mass or keener ears. After all, as real life Humans, we see plenty of animals that are more acrobatic, athletic, and perceptive than we are. Even some skills can be attributed to some magical property of the race, such as an innate connection with animals, but I feel that such explanations should be used sparingly and don't work for every situation. Thus, I have removed such proficiencies from the racial traits and features of my races and moved them here: to Heritages.

Heritages

Administrative

Administrative communities are rare and, by their very nature, only exist in larger societies with sufficient central authority and organization. Administrative communities are often national capitals and their role is to collect taxes, manage militaries, and decide policy. The leaders and administrators who perform these jobs form the core of the community's economy and many supportive and supplementary jobs exist to facilitate these officials.
You are proficient in History and Investigation.

Agrarian

Agrarian societies are societies which live a life predominantly of subsistence farming. While most communities will have farmers who grow enough that they can trade for tools or livestock from their neighbors (who aren't farmers), the majority of the population grows at least a portion of their own food. Most agrarian communities are largely self-sufficient, but rarely particularly wealthy.
You are proficient with Athletics, Nature and with either Brewer's Tools or Cook's Utensils.

Artistic

An artistic community comes in many forms: a commune, an academy, a traveling show, and others. What unites the people of this community is their attachment to creativity and art of some form or another. Such communities have members which are not artists. Someone has to feed, manage, and maintain everything, after all, but such people seldom attach themselves to an artistic community if they don't have at least a passing interest in the type of art being created. They may simply dabble, or they may be aspiring artists themselves, eager to find a mentor or be given their chance to shine.
You are proficient in either Performance or Sleight of Hand. You are proficient with either a Game Set or an Instrument of your Choice. You are proficient with either a Disguise Kit or with Painter's supplies.

Elite

You grew up among the upper crust. This is most often the ruling class, perhaps even actual nobility. Regardless of their exact nature, their influence cannot be denied and their wealth often speaks volumes. Not every society has such Elites, but, by definition, the ones which do have a sharp contrast between their lifestyle and the lifestyle of the other citizens.
You are proficient with Deception and Persuasion

Fishing

Whether on the ocean's coast or along the might rivers of Arterra, Fishing communities are one of the most common. Much like agrarian communities, fishing communities are largely self-sufficient. However, due to the proximity of water often limiting the amount of usable land they have access to and ready access to waterways, fishing communities are more inclined to trade their extra fish for the things which they cannot produce themselves.
You are proficient in Nature and Water Vehicles.

Forestry

Forestry communities exist in or near woodlands and these woodlands for the backbone of their lifestyle. From wood cutting, foraging, and hunting are all key elements of Forestry lifestyle. What distinguishes them from hunger-gatherers is the increased permanence of their settlements and a greater percentage of farming. While forestry communities do not rely on farming to the extent of agrarian communities (indeed, they often lack the land necessary to do large-scale farming) most members will grow small gardens or keep small numbers of livestock on hand to supplement their diet.
You are proficient in Acrobatics and two of the following: Herbalism Kit, Carpenter's Tools, or Woodcarver's Tools.

Hidden

Hidden communities are isolated and, well, hidden. Their people, for whatever reason, have chosen to withdraw from the world at large to such an extent that they actively try to prevent others from finding them. Secreted in deep forests, remote valleys, or distant islands, hidden communities are both rare and varied, but all share a commitment to the secrecy of their homes. By their very nature, hidden communities are as self-sufficient as they can be, though they occasionally send members out or rely on a few trusted allies for trade or purchase of things they cannot produce themselves.
You are proficient in Stealth and Survival.

Hunter-Gatherer

Hunter-Gatherer communities are among the most fluid communities. They live a life of foraging fruit, mushrooms, nuts, and wild plants along with hunting game. Because doing such things takes so much time and yields so little food by comparison, there is very little division of labor and nearly every able-bodied member contributes by joining in one of a very few activities. Hunter-Gatherer communities are also often transient, moving from place to place to allow areas to replenish themselves, but this is not always the case, especially if a community happens to live in a particularly bountiful location./
You are Proficient in Survival and your choice of two Simple Weapons.

Industrial

Industrial communities rely on industry. Their members are craftsmen and artisans who create goods for sale. They form a stepping stone between gathering communities such as forestry and mining communities and mercantile communities. Industrial communities often have a small population of people who harvest natural resources but most of their raw material is purchased or traded from other communities. Similarly, industrial communities also have some members who sell the community's wares, but such people are few and typically sell to a limited market. Perhaps trade caravans pass through the industrial community and purchase their goods to sell at a busier market town. Perhaps the Industrial community is located in an out of the way place and its traders sell their goods to the next geographic link of a long chain of communities beginning with those which gather the resources and ending with bustling trade hubs.
You are proficient with your choice of two of the following: Alchemist's Tools, Carpenter's Tools, Cobbler's Tools, Glassblower's Tools, Jeweler's Tools, Leatherworker's Tools, Mason's Tools, Potter's Tools, Smith's Tools, Tinker's Tools, Weaver's Tools, Woodcarver's Tools.

Magical

Magical communities are centered around magic, typically arcane magic. These communities highly value arcane aptitude and most of their members know at least a few basic cantrips and have some knowledge of magical theory and application. Such communities may be an enclave of sorcerers who share a common font of power (such as a common draconic ancestor), a collegiate community of wizards dedicated to the study of magic, or a community that happens to exist in a place where ambient magic pervades the area.
You are proficient with Arcana. You may also learn one Cantrip of your choice from either the Bard, Wizard, Sorcerer, or Warlock spell lists.

Mercantile

Mercantile communities sell things and make their living doing so. They may produce such goods themselves for sale, they may explicitly source goods from industrial communities, but most arose in places where travelers frequently pass and congregate. They purchase goods from travelers who come from certain areas and sell them to travelers from others. The defining feature of a mercantile community's economy is that they export goods to people from other locations, rather than selling or trading such goods among themselves as communities such as agrarian communities do. In doing so, they form a vital link in the flow of goods and ideas throughout the world. As noted, some mercantile communities do produce their own goods, but the percentage of the population which does so is either small or has significant overlap with the percentage who sells it to outsiders.
You are proficient in Persuasion and your choice of two Languages.

Militant

A militant community is one which is defined by their military. Typically these are towns which arise around military garrisons, but they can also be a community that has had to endure many attempted invasions and gained skills accordingly. Militant societies are not typically aggressive on a wide scale (see Raiding communities for that kind of military community), but may regularly engage in hostile actions against specific targets.
You are proficient in Intimidation and a single martial weapon of your choice.

Mining

Mining communities are exactly what they sound like. Communities which extract raw resources from the ground. Ores, gems, clay, stone, all of these resources and others come from mining communities. Mining communities are composed primarily of the miners themselves, who engage in a rough, physically demanding, and often dangerous occupation daily. Expect those miners who are not gruff and taciturn to be a font of gallows humor.
You are proficient in Athletics. In addition, you may ignore the penalties of rough terrain caused by rocky situations (such as landslides, rubble, or scree) as well as by uneven stonework (such as a natural cave or a damaged stone floor).

Monastic

Monastic communities are similar to hidden communities, but are not hidden. They tend to be isolated and often do not accept visitors, but make no attempt to hide their existence. Monastic communities are comprised of monks, philosophers, or the like and those who attend to them. Here they meditate and contemplate the various mysteries of the universe. Most monastic communities strive for self-sufficiency, but some prefer instead to focus on particular output (often some kind of crop or edible goods) which they sell for the other supplies they may need.
You are proficient with Insight and with your choice of the following: Arcana, Medicine, Nature, or Religion.

Nomadic

Nomadic communities are groups of people, typically small in number who roam from place to place. They often have routes they take year after year and territory they have established as theirs, but in some uncommon cases, they simply travel idly with no intended destination or direction. Nomadic communities do remain in locations for a time, often setting up tents or other temporary dwellings, but such settlements are gone within months as the nomads have moved on to the next leg of their journey. Most nomadic communities stay within a particular type of climate or terrain on their travels and, in doing so, become experts as traversing its dangers.
Your speed is increased by 5ft. Additionally, you may choose one type of terrain: Forest, Mountain, Tundra, Desert, Swamp, Grassland, or Cave. You ignore the movement penalty for difficult terrain for situations related to that terrain. This applies to both mundane and magical obstacles, so long as they are obstacles that would occur naturally with regularity in that terrain. For example, a nomad who is familiar with forests may ignore movement penalties from undergrowth, vines, and the like, regardless of where they are encountered and whether or not they are magical. However, they would still be slowed down by scree or rubble (from either a natural landslide or a spell which creates rocky terrain), even if it is encountered in a forest.

Pastural/Herding

Pastural and Herding communities are similar to agrarian communities in most aspects. However, instead of focusing on the growing of crops, these communities are centered around the raising of livestock. Like agrarian communities, pastural and herding communities do not see much division of labor and virtually everyone has livestock. Many supplement their diet with small gardens and tend to their own needs in regards to clothing, tools, and the like, but may trade such extra animal products as they can produce for these things. Members of such communities often spend long hours alone while tending their livestock.
You are proficient with Handle Animal, Land Vehicles, and your choice of one instrument.

Raiding

Raiding communities generate most of their income by taking it from others. Either foods and goods which are used by the community itself or valuables which are sold or traded. Typically the raiders themselves make up a relatively small percentage of the population, with the remainder occupied in small scale farming or industry, but this small group forms the core of a raiding community's identity and prosperity. Exceptions exist and communities that devote the bulk of their population to the actual act of raiding are frightening enemies able raise large, if often disorganized, armies and strike unsuspecting targets without warning.
You are Proficient in Perception and one martial weapon of your choice.

Sailing

Sailing communities are similar to fishing communities and there is a lot of overlap, but rely more heavily on actual vessels. While fishing communities can exist anywhere there are fish and its fishermen can readily fish from the shore, a sailing community requires access to open waterways. Though the number of members who actually venture away from the community for prolonged periods of time may be a small percentage of the population, that is not always the case, and even those who remain home typically have plenty of experience plying local waters.
You are proficient with Water Vehicles, Navigator's Tools, and Use Rope. If your campaign is not making use of my homebrew skills (such as Use Rope), you instead gain proficiency with Perception.

Scholarly

A scholarly community is typically centered around a school or university and most of its permanent population exist to facilitate the operation of such an institution. A scholarly community's permanent population is often overshadowed by the population of its students, many of whom are transient. Scholarly communities are often at the peak of technological and/or magical research (at least, for the area).
You are proficient with Investigation, one language of your choice, and Use Device. If your game is not using my custom skills (such as Use Device) you instead gain Proficiency with your choice of one of the following: Arcana, History, Nature, or Religion.

Slave

Slave communities are based on the labor of an enslaved group of people. These slaves typically rival, if not exceed, the population of free citizens and typically live in squalor. Slave labor is typically menial and physical, though some slave communities are more akin to industrial communities. Regardless, the fact that the community's prosperity relies on slave labor fundamentally alters its dynamic from the more egalitarian industrial or mining communities.
If you were a member of the free caste, you gain proficiency with Intimidation and Use Rope. If your campaign does not use my custom skills (such as Use Rope), you instead gain proficiency with Perception.
If you were a member of the slave caste, you gain proficiency in Athletics and gain the Powerful Build feature.

Slums

A catch-all term for various communities living in poverty, specifically in the shadow of much more wealthy communities. These communities are full of desperate people trying to eke out an existence in a larger society that they cannot find a place in. They may be forgotten or deliberately excluded, but whatever the reason, they are defined by their inability to reliably get what they need to live comfortably, or, in extreme cases, even survive at all. As a result, many members of such communities turn to criminal activities, ranging from pickpocketing to outright murder in order to make ends meet. While most would prefer to target the wealthier (whom they often accuse for their situation) some are perfectly willing to prey on their fellow residents, especially if it means the difference between starvation or sustenance.
You are proficient in Deception and Sleight of Hand.

Technocratic

Technocratic societies are similar to scholarly societies, but are focused more on the application and creation of new technology. They eschew study of esoteric subjects and magic in favor of invention and engineering.
You gain proficiency with Tinker's Tools, Smith's Tools, and Use Device. If your campaign does not use my homebrew skills (such as Use Device), you gain proficiency in Investigation instead.

Theocratic

Theocratic societies are ruled by their spiritual leaders and their religious devotion is the backbone of the community. Some theocratic societies are merely communities where particularly devout worshippers of widespread religions gather, but others are dangerous collections of fanatic cultists. The religious leader may have been elected or chosen in some other way, or they may have used their natural charisma to gather passionate members and bend their fixations on a divine entity or belief, often with themselves as a central figure, if not the focus of the religion itself.
You are proficient in Religion. In addition, you know one Cantrip from either the Cleric or Druid spell list.

Tourist

Tourist communities make a living on travelers. While they often sell merchandise like a mercantile community, the main draw of outsiders comes from some landmark or quality of the community itself. This can take many forms, from famous buildings, to holy sites, to communities situated in an area of great natural beauty. Sometimes the community itself is a famous landmark, such as the home of a heroic figure or a community which forms a key part of a nation's history. Unlike a mercantile community, which focuses on selling goods to outsiders, tourist communities focus on selling services to outsiders. Tourists come to see the sights, and they are willing to pay hefty prices to stay at the most luxurious inns and eat the most delicious meals. They're even willing to pay to see tours of the landmark in question. The most important skills for residents of a tourist community is to identify what their clients want, are willing to pay for, and to put on a good show to seal the deal.
You are proficient with Insight and Performance.

Creating your Own Heritages

As sure as people are varied, so too are their communities. There are plenty of other models which are not covered by those listed above. If you choose to create your own heritage, work with your DM to select two skill or weapon proficiencies (either of these may be substituted with two tool proficiencies) which a member of the community would likely be familiar with. Remember, these are skills which the majority of the community are likely proficient in, even if it is not directly related to their profession. They are skills citizens can pick up by interacting with their neighbors. If your heritage is describing a type of person with specific training and expertise in a trade or profession, you're creating a background. A heritage is the culture of the community you're from, a background are skills related to your specific role within that community. To avoid making backgrounds obsolete, try to save creating a heritage for only those instances where a niche exists that none of the existing heritages come close to filling. Otherwise, try to instead apply the heritage that is most applicable.

Changing Heritages

Generally speaking, heritages don't change. You only have one childhood, after all. That being said, given sufficient downtime your DM may allow you to replace your heritage if you are living in a different kind of community and are likely no longer practicing your previous skills. This should be done sparingly and requires years, maybe even decades of time spent living in a new community. "Living" is the key phrase here. A character who owns property in a fishing village but spends 8 months on the road adventuring is unlikely to really immerse themselves in the lifestyle of their community.