- CP/M-65 - Atari and OSI ports, DwarfStar
- adlib2vgm - Converts file formats supported by AdPlug to VGM format
- pokeysynth - Atari Pokey LV2 synth plugin with FLTK
- am6070towav - Convert AM6070 ROMs to WAV files
- osiemu - Ohio Scientific Instruments, Inc. Emulator for Linux, Windows, and macOS
- atari8080 - Intel 8080 Emulator in 6502 assembly (prototyped in C)
- atarisid - Software SID emulation for the Atari 8-bit (6502 @ 1.8MHz + POKEY)
- fake6502 - MOS 6502 Emulator in C
- break6502 - 6502 gate level simulation in C++
- atariterm - atari800 emulator in a vt100/ANSI terminal window or console
- saprtools - Tools for manipulating or creating Atari 8-bit SAPR files
- pokey-explorer - Exploring the Atari 8-bit Pokey chip
- random6502 - Pseudo Random Number Generators in 6502 assembly
- xatmas2 - Atmas 2 Compatible 6502 Cross-Assembler
- 8x8-fonts - Collection of very old 8x8 fonts
- siddasm2 - NSF, SAP and SID file disassembler (NES, Atari and C64)
- sizecoding - Sizecoding on retro computers! Atari 8-bit, C64, and more
- romdos - Atari 8-bit ROMDOS archeology and new experiments
- ramtest2114 - MARCH MSS 2114 SRAM Tester
- PicoRAMCart - Emulate Raster/Bob!k/C.P.U. RAM Cartridge with A8PicoCart
- atari2600cart - Atari 2600 Cartridge PCB
- bat-detector - Detect bats
- cs9236-waveblaster - CS9236 WaveBlaster card
- project-helena - Atari 800XL keyboard replacement
- vs1053-waveblaster - VS1053 WaveBlaster card
- 1088xel-kicad - MyTek's 1088XEL in KiCad
- midimuse - MIDI Interface for the Atari 8-Bit Computers, including a WaveBlaster Interface
- snes2joy - Connect SNES controller to Atari joystick port
- cygcross - Building a Cygwin Cross-Compiler for Linux
- zmalloc - Dynamic Memory Allocation for Small Memory Systems
- 7400-logisim - Logisim library of 7400-series ICs
- zzjson - Lightweight JSON library in C
- fpm - Fixed Point Math library
- cpm22-from-source - Build CP/M 2.2 from source
- frida - FRee Interactive DisAssembler
- myterm - Simple vt100 terminal based on SDL