Stuff I've made for OSR (i.e. primarily TSR D&D and close derivatives)
DUNGEON PLANET preview edition - part of an outer space megadungeon suitable for level 1-3 characters.
HELL METRO - a 0-level funnel inspired by 80s/90s Japanese media. The rules are OSR-based but differ from published rulesets so you'll need to homebrew if you want to continue to level 1+
IN THE CLUTCHES OF THE COMPUTER-GOD - An unfinished Labyrinth Lord I have no interest in completing.
VILE VENGEANCE OF THE BEES - bees discover metallurgy. Bloodshed ensues. Probably best for levels 2-5.
Bestiaries, Monsters, etc.
Abomination Appendix Volume I - A collection of converted creatures with a slight underground theme: Burrowers, cave giants, kongamoto, merrow (5e version), miasma serpent, avesa rakshasa, tunnel brute.
Abomination Appendix Volume II - Featuring OGL versions of the Monster Manual 2's Pseudo Undead: False ghasts, ghouls, liches, mummies, skeletons, specters, vampires, wights, and wraiths.
Abomination Appendix Volume III - Three new dragons: Brown, orange, and sea. Appendix of the appendix is unfinished and sea dragons kinda suck but oh well.
Abomination Appendix Volume IV - OGL version of Monster Manual 2/Fiend Folio monsters: Bua, fellknight, lulushou, reverse troll, slime maiden, strangler gnome.
AD&D monster list with OGL status, sources, and alternatives - What it says in the title. Features both OSR and non-OSR OGL sources. Currently on 9th revision.
Baatezu, Greater, Uniila - converted from Pathfinder
Frost Fir - converted from Pathfinder
Gods, Demigods, & H'orderves Volume I - Have your PCs wanted to eat members of the Olympian Pantheon? Now they can!
Leonin, Mirrodin - converted from Magic: the Gathering
Rakshasa, Amanusya - converted from Pathfinder
Shabti - converted from Pathfinder
Sphinx, Cyno- - converted from Pathfinder
Zombie, Mirrodin - converted from Magic: the Gathering
Classes & Races
The Dynonik - Deinonychus-folk for B/X
The Human - The long-lost B/X racial class.
Settings & Places
PLANES OF GARBAGE - satire of artsy-fartsy "OSR" books or a work of high art masquerading as a satire of artsy-fartsy "OSR" books? You decide.
Sanctuary - a demi-plane that serves as a "traditional" starting area for weird settings.
Barbarian or Humanoid Tribal Name Generator - includes 5 sample tribes.
Guns - One-page (technically half-page )firearm rules. Features art!
RUNES - mini-supplement for magic runes.
Terrors & Wonders v0.1 - abandoned not-quite OSR game
Terrors & Wonders v0.0