As a quarantine project last year, I scoured PD pulp sources, culled a bunch of images, cleaned them up and populated them into a set of four 6"x9" books, each featuring 45 new monsters (based on these classic images). Book three also includes some animal-related spells, and book four includes some new B/X psionics disciplines. They are statted up for B/X (so that's makes them compatible with all those similar editions and retro-clones). And easy enough to adapt for white boxers and first editions.
I just finished writing book #4. The first three have already had a first edit (and a pre-release at the most recent NTRPGCon), and we'll do another proof on those over the next couple of weeks as we edit the final book. We'll order test copies of the box, and look to make these available (as a boxed set) by August.
Once released, PDFs will be available as a bundle through DriveThruRPG.at a super great price ($1 for all four). Individual books will be available POD through Lulu.com, and the boxed set will be available directly through the NBD storefront (looking like the boxed set will sell for $30 + shipping).