AD&D 2e House Rules

1. Everyone can reroll one character's ability scores one time per campaign at character creation for any reason.
2. If a character has no score above a 6 or has ability scores totalling 60 or less at character creation, the character's ability scores can be rerolled.
3. Every character starts with 2 Iron Rations and 1 Waterskin for free. Additionally, Mages and Specialist Wizards begin with a spellbook and Clerics and Paladins begin with a holy symbol of their deity.
4. Everyone can read and write their native tongue. Reading/Writing can be gained for other languages at the cost of 1 language slot each. Sign language for a language (if applicable) can be learned at the cost of 1 language slot each.
5. Weapon speed is not used.
6. Side-based d6 initiative is used. The winning side can forsee some of what the losing side plans to do and react accordingly due to quick reflexes.
7. Characters no longer die at 0 hit points, and are instead On Death's Door.
8. Each Small- or Medium-sized creature needs only 1 waterskin per day, rather than 2.
9. Thieves can backstab a creature multiple times, but still only in the first round during which they enter combat. The thief need not use a stabbing implement either, and can use a club, mace, or similar weapon. If the thief is dual wielding, they can backstab with both weapons during their first turn.
10. Thieves can backstab with a ranged weapon, but must be within the short range of the weapon and do not gain the normal bonus for striking with a melee weapon from behind (+4 for a thief normally).
11. A first level character starts with a minimum hit point total equaling to the average starting hit point roll (half die maximum +1).
12. Single-classed fighters gain the Cleave ability: If a fighter inflicts enough melee damage to reduce an opponent’s hit points to zero or fewer, the fighter can immediately attack another opponent within melee range using the same weapon. The fighter can continue attacking new opponents as long as the above requirement is met to a maximum limit of 2 + the Fighter's Dexterity Reaction Adjustment.
13. If a Mage/Specialist/Bard fails to learn a spell, they can attempt to learn it again if a) they gain a level, or b) they come across a different instance of the spell.
14. A shield grants its normal -1 bonus to AC, and can absorb the damage from a single blow, but then is rendered useless. Large shields can absorb 2 hits, and magic shields can absorb an additional number of blows equal to their enchantment bonus. This does not reduce the bonus of the shield, but when it breaks, it is still broken entirely.
15. All shields can block attacks from any space in front of the character.
16. A metal helmet can absorb the damage from a single critical hit, but then is rendered useless. Wearing a metal helmet imposes a -1 penalty to Surprise.
17. XP can be gained through Feats of Exploration in addition to normal means. This replaces class-specific XP bonuses.
18. PCs can choose to carouse or practice philanthropy for experience.
19. 16 in all Prime Scores grants 10% Bonus XP regardless of class, and a 14 in all Prime Scores grants 5% Bonus XP. For example, a Bard with 14 Intelligence, 16 Dexterity, and 16 Charisma will gain 5% Bonus XP rather than nothing.
20. Mages, Specialist Wizards, Bards, Clerics, and Druids can create spell scrolls and potions beginning at 1st level rather than 9th level, but must expend both XP and GP in order to do so until they reach 9th level, at which point they no longer need to pay XP costs unless otherwise stated.
21. Weapon Mastery replaces the typical Weapon Specialization useable by single-classed fighters, opening up the system to all classes, while still benefiting Fighters most, then warriors, then other classes.
22. Alternate Starting Wealth can be used on GM's suggestion.
23. A Mage, Bard, or Specialist Wizard actively learning a spell from another mage, bard, or specialist wizard—as opposed to learning the spell just from reading a spellbook—gains a 10% bonus to their Learn Spells check to learn that spell due to the guided instruction granted by the more learned caster.
24. When using a weapon in an improvised form, such as striking with the flat of a blade to deal bludgeoning damage, you treat the weapon as though you are not proficient. This penalty stacks with any pre-existing non-proficiency.
25. Specialist wizards have altered spell lists, shown in each of their class articles.