REX
A few more ROMs (just Disk+2.0 and MFORTH are different from what's in the roms zip from the REX docs. Disk+2.0 hasn't been uploaded anywhere before, and MFORTH is a newer version than in the roms zip.)
Some roms in the roms zip from the REX docs have been patched to work better with REX, so generally you want to use those copies specifically rather than other copies of the same roms.