There are 2 repositories under retrocomputers topic.
A stand-alone, BASIC-programmable microcontroller and microcomputer in one! The fastest, cheapest, most hackable 8-bit computer ever.
This is a reconstruction of the original 1981-82 IBM PC BIOS source code using scanning and transcription of the BIOS listings found in the IBM Technical Reference manuals.
Open Hardware 8/16/32 Kb Cartridge for the Commodore 16, 116 and Plus/4
This is a small adapter, in the form of a daughter board, which fits into the socket of the "Sally" CPU of the Atari 800XL microcomputer. It replaces that CPU with a CMOS, modern, low-power, fully static, currently in production W65C02S and some auxiliary logic. The project has been featured in three videos in my YouTube channel ("The Byte Attic," https://www.youtube.com/channel/UCfzZNuoHys1t-AdwYDhOz8g).
A virtual Atari ST disk over serial for Windows, Linux and macOS
Reverse-engineering documentation about the Q1 microcomputers, the world's first true microcomputers (1972) with integrated microprocessors.
Open Hardware 64 Kb RAM Expansion for the Commodore 16
Draegerman for Agon Light and Console8
A BBC BASIC v3 port of the horror interactive fiction game coded for the Commodore 64 by Mark S. Boucher
Jotto 2020 is a word puzzle game that cleverly combines the game mechanics of the games, Jotto and Mastermind.
NOMIS: a clone of the classic game SIMON for AgonLight and BBC BASIC SDL
Snac-Snake: a variant of the classic game Snake for AgonLight and BBC BASIC SDL
An original game inspired by tower defense games and Tetris
Remastered version of my 1993 arcade game Androidz
BBC Basic and Assembler version of Polymer Picker game.
Our README.md!
Setting up SGDK with Visual Studio Code for a portable enviorment, SGDK and a mega drive emulator (gens) is included.