I think I’ve stumbled on this site before, but it seems not to have been mentioned here. If you’re looking for an Algol, APL, Modula2, Pascal, Cobol, MUMPS, Fortran, C, a Basic or even a 6502 cross assembler for your CP/M machine, it might well be in here:
Welcome to the Retrocomputing Archive!
Oh, and DOS offerings too, and even something for your IMSAI.
via Willard Goosey who mentions a mirror of the Garbo PC Software Archive within.
See also
My retro archive, large 6502 update