Gnomes

Rare and eclectic, gnomes tend to gather in small, out-of-the-way settlements where they need not worry about being tread upon by all the "big people" of the world. This is not to say gnomes are unheard of in mixed civilization; on the contrary, gnomes that do opt to intermingle find that their natural proclivity towards spellcraft and tinkering is a welcome addition to any community.
Biologically, gnomes share a common ancestor with dwarves and halflings, but somewhere along their genetic line, they developed a natural connection with magic. This tends to manifest through a gnome's ability to imbue simple materials with magic, conjure whimsical illusions, or blend into their environment to an almost supernatural degree. This magical aptitude is also generally considered to be the source of their longevity, with most gnomes living for several centuries (assuming they don't blow themselves up first) to up to half a millennia. 
Like their dwarven cousins, gnomes' longevity allows them to embark on projects or journeys that would consume most (if not multiple) of a human's lifetime. Unlike dwarves, gnomes are more than willing to uproot everything and start from scratch should a new idea surface. There brains make up a not insignificant amount of their limited biomass, and they are intensely curious creatures because of this; often to a fault. A gnomish tinkerer is more interested in figuring out the solution to a problem or the explanation to a phenomena on their own rather than consult the writings of someone who's already written a tome on the subject. 
Gnomes have also developed an unbelievably complex and often convoluted language system, as evidence by their penchant for very, very long names. This disregard for brevity often expands to the names of their settlements. As it turns out, the average man, dwarf, or elf is generally incapable of retaining or pronouncing Migingwaith'barnaltha'I'clochrin, so most gnomes have taken to coming up with amusing alternative names that are easier on poor outsider brains; many of them bearing the word "gnome" in it. For example, the aforementioned gnomish settlement is known colloquially as Autognomia.