I use RISC OS for development purpose. Maybe you could add it with its name. I don't like to tick 'other' boxes ;-(
Atari 1040 STE+SATAN, 520ST, 800xl, xegs, Amiga 500, 2000 with 68020, Archimedes, RISC PCs + Iyonix, Omega, BBC B, Atom, Electron, ZX 81, Spectrum 48/128/+2/+3, Speccy2010, Russian clones, Sam Coupe, V6Z80P, QL with accelerators, Enterprise 128, Einstein inc 256, Oric Atmos, MSX 1, 2, Thomson MO5, Amstrads inc CPC+, C 16, 64, 128, VG5000, Apple IIGS and more ! Yes I want to create a museum when I retire.