I don’t cover DC here, but in the late ’80s, Gil Kane did some great work on a series about The Atom. So he’s a great choice for an Ant-Man/Spider-Man team-up. In the 1990 annuals, Spidey shrinks down, eventually getting small enough to have an adventure in the Microverse.
All three Spider-title Annuals came together for 1990’s Totally Tiny Adventure: Amazing Spider-Man Annual #24. Spectacular Spider-Man Annual #10. Web of Spider-Man Annual #6.
He gets shrunk and teams up with Ant-Man. They go to the microverse and meet Psycho-Man.
That’s pretty much it. Except the bondage.
Lots of fun, and the A-list writers and artists didn’t hurt one bit.
There’s also several back-ups for each annual. Solo,. Prowler. Silver Sable. Sandman. Rocket Racer. Abe Brown from the old Sons of the Tiger. And Aunt May taking down some terrorists while Punisher watches on (don’t ask ). Steve Ditko actually draws one of them.
So the fact that there’s not much to this story isn’t as bad–it’s basically three normal-size comics–not three giant annuals.