House rules and revisions for first edition AD&D
From the introduction:
These house rules are for playing AD&D first edition. They need the original PHB, DMG, and UA (or clones). They are for use in a fairly generic campaign with no settings quirks. The variant rules replace parts of the original rulebooks, so it helps to know the PHB and DMG. Original rules et alia apply unless replaced. Topics are covered compactly, sometimes in note-like form. The less fiddly bits of UA are used, with some Basic D&D and 2E ideas. There are many tweaks and changes. These revisions are for my own campaign and reflect personal preferences (e.g. using mage because it’s shorter than magic-user), but are published for the role-playing community in case others might find the ideas and reworkings interesting or useful.