4) The Watchers
Though they appear in the same scene as Stan Lee’s cameo, the inclusion of the Watchers is so major it deserves its own entry.
Yes, the haughty-looking, bulbous-headed aliens that Lee is seen with are, in fact, the Watchers. In Marvel comics continuity, the Watchers are an ancient race of powerful beings who are sworn to observe the universe but never interfere. Uatu is the Watcher assigned to Earth’s solar system and he often bends the Watchers’ code by visiting – occasionally allying with and occasionally antagonizing – the Avengers.
It’s long been theorized by fans that Stan Lee has been playing Uatu in disguise all along, which would explain why he’s always hanging around superheroes. Depending on how you read this cameo, that theory is either confirmed or ruled out. Stan doesn’t appear to be one of the Watchers here, but it isn’t outright stated that he’s a mere human, either.