So... this is one of the things I've been working on during "my COVID year." I culled a number of public domain illustrations from a host of pulp magazines, and started writing descriptions for them as B/X monsters. It has manifested itself as three 6"×9" books, each with 45 monsters and about 60 pages. The creatures are all named and divided into the books. The layout is 95% complete, but copy for the entries is only about 33% complete. My goal is to have these ready for the upcoming NTRPGCon. So until that gets closer, no use in asking how they're coming.
BTW, these are generally unrelated to the Creature Compendium II, which is still a possible/ongoing thing. Though, the creatures from these might make it into that (with new drawings to replace the PD images).