1.In Spider-Man: Into The Spider-Verse, which takes place in the Miles Morales altered-universe, his test date says "Decembruary."
2.Also, on the poster of Chance the Rapper in Miles' room, Chance is wearing a "4" hat instead of his signature "3" hat, further emphasizing a different universe.
3.In Spider-Man Noir's introduction scene, we see an ad for an EA Water Polo video game, a game that does not exist in our universe.
4.The Brooklyn bridge seen in the final fight scene between Miles and Kingpin is a reference to the color scheme of the bridge seen in the opening title sequence of Daredevil, where Kingpin is also the main villain.
5.The ghost of Kingpin's son looks like Matt Murdock, AKA Daredevil.
6.Stan Lee is seen in the movie as the store clerk who sold Miles his Spidey suit, but he's also seen here walking over Peter B. Parker and Miles.
19.In both Into the Spider-Verse and Spider-Man 2, Doc Ock is the one who throws a car through a restaurant.
20.Before she's revealed as Gwen Stacey/Spider-Woman, "Gwanda" tells Miles to "just relax" when he gets his hands stuck in her hair, a tactic he has to use in the movie to unstick from things, symbolizing that she knew who he was before he did.
21.Miles' Spidey-movements at the end of the film are direct movements he learned from Peter B. Parker at the beginning of the film.
22.And finally, here you can see a shot of the FLDSMDFR from Cloudy With A Chance of Meatballs, perhaps because Michael Kurinsky and Danny Dimian worked on the visual effects for both Spider-Verse and Cloudy.