There are 12 repositories under apple2 topic.
A latency-hating emulator of: the Acorn Electron and Archimedes, Amstrad CPC, Apple II/II+/IIe and early Macintosh, Atari 2600 and ST, ColecoVision, Enterprise 64/128, Commodore Vic-20 and Amiga, MSX 1/2, Oric 1/Atmos, early PC compatibles, Sega Master System, Sinclair ZX80/81 and ZX Spectrum.
Ted Fried's MicroCore Labs Projects which include microsequencer-based FPGA cores and emulators for the 8088, 8086, 8051, 6502, 68000, Z80, Risc-V, and also Typewriter and EPROM Emulator projects. MCL51, MCL64, MCL65, MCL65+, MCL68, MCL86, MCL86+, MCL86jr, MCLR5, MCLZ8, MCL6809
AppleCommander is a tool that manipulates Apple ][ disk images. Files may be imported, exported, viewed, or printed with various file filters.
Awesome Lists of retrocomputing resources (6502, Apple 2, Atari, ...)
An Apple IIgs Emulator and Debugger written in C/C++ for Windows, Linux and macOS
Allows Acorn BBC Microcomputer language ROMs to run on Apple //e enhanced, //c and IIGS.
Tool for working with Apple II and vintage Mac disk images and file archives.
Portable chess game in C. Commodore 64, Apple 2, Atari, Oric, Commander X16, curses terminal, etc.
Vim syntax highlighting for the ca65 assembler
Apple II FPGA Co-Processor
Apple ][ //e HGR Font Tutorial
Apple II ProDOS-8 system files that run on startup and install clock drivers, ramdisks, and other utilities
DSKalyzer Apple II disk image management tool
ZX Spectrum Manic Miner game for the Apple II
The Eight Bit Algorithmic Language for Apple II, Commodore 64 and VIC20
File management utilities for the ProDOS operating system on the Apple II
Roland Gustafsson's RWTS18 source code.