Info-ZIP portable compression/archiver utilities (Zip, UnZip, WiZ, etc.)
A small, self-hosting 16bit Forth system
VolksForth is a 16bit Forth System with the goal to produce a manageable Forthsystem for computer systems with restricted system resources.
A fast, unobtrusive and modern cross-platform GUI toolkit. Agar fully exploits hardware acceleration where available, but also supports simple frame-buffer interfaces. Agar is stand-alone and easily portable to new platforms and graphics systems.
Circuit simulators like SPICE for low memory computers
SPECI-SPICE is a subset of SPICE intended to run on low powered computers like Amstrad CPC, ZX Spectrum, CP/M machines, old PC machines, some programmable calculators,etc. by keeping most important functionality of SPICE 2.