Sep 1962 - STRANGE TALES ANNUAL #2 - Spider-Man

I assume the cameos you mention are things like Thor flying overhead in ASM annual #1 -- appearances that do not influence the story.  In the case of AVENGERS #11 the appearance *does* influence the outcome of the story.

As an aside, I'm quite astonished (pun intended) that Spider-man wasn't used all that often in guest appearances and crossovers in the Silver Age.  When you hear Stan today talk about Spider-man as their 'breakout hit character' I almost expected them to begin exploiting that potential right away but that really didn't ramp up until the Bronze Age.

Just looking at the number of guest appearances in the list above you would think that Marvel's 'breakout hits' were the Hulk and Namor!

Interesting list you have there. Now that has me wondering about the villains. Did they tend to expressly belong to a hero, or how much cross pollinating happened?

A lot of Spider-man villains made appearances in other books.  Daredevil tackled Electro early on in his book.  The Sandman tussled with the Human Torch in STRANGE TALES before joining the Frightful Four and transitioning to a regular FF villain.  The Scorpion battled Captain America in the late Silver Age.  The Kingpin pretty much became a Daredevil villain after a certain point.

Spider-man seemed to mostly battle his own villains in his book with the notable exceptions of DoctorDoom and The Ringmaster/Circus of Crime (who started as Hulk adversaries).

I remember some other early ones -

Magneto vs. Thor

Count Nefaria vs. Iron Man

Count Nefaria vs. X-Men

Masters of Evil (Black Knight, Melter, Radioactive Man, Enchantress Executioner) vs. Avengers (vs. their arch nemesis, but in a different book)

Ox (from the Enforcers) vs. Daredevil