Whizbang Dustyboots
Gnometown Hero
C&C is crazy compatible with everything through 3E, which is one of its biggest strengths.It is monster stat block compatible with most of the other OSR D&D pseudoclones and retroclones.
If I went back to it, I would probably use the Monster Overhaul as my bestiary, plus the grue from Monsters & Treasure. (After backing Classic Monsters, I discovered that I really don't want to use Fiend Folio or Monster Manual II monsters for the most part nowadays. My DMing style has evolved.)