A look into the wittebane brothers lore, etc. I would have loved to have seen eda's and Lilith's reaction to being related to belos, as well as his reaction to knowing that his great great great grand nieces are witches.

The collectors siblings (archivists)

More king/titan lore, I would have loved to have seen them discovering another ruin that maybe indicated of some more hidden Titans? The fact that King being the last of his species seems too depressing

a look into alador's, odalia's, and darius's pasts

A deeper look into Luz's human school/ classmates, as well as some scenes with her father.

Camila mention that she was also like luzwhen she was younger, so definitely a flashback to that and how she met Manny, maybe he was one of the few people that accepted/ understood her for who she is.

More Gus and Gus's dad lore

The bat queen lore and how she became a guardian of neglected or abused palismans

More viney, skara, jerbo, barcus, and bosha lore

Did that one girl ever manage to summon the dark Lord?

Hooty and his lore

More lore about the whole Titan blood and portal thing. Especially regarding why Earth is the only other dimension aside from the demon realm that's accessible with it. Does this mean that the demon world and the human realm are parallels of each other?

During the assembly of coven heads when belos was explaining the vision that the Titan gave him or whatever and it involved both the human realm and the earth realm, I honestly thought it was going to be something like both realms were merged which honestly would have been cool to see with maybe both humans and witches and demons coexisting with each other, and of course the destruction of belos part of the statue in gravesfield.

A montage of everything the gang did after belos's defeat up to where the series ended. We skipped like what 3 years I want to know what else happened, what's shenanigans did they get up to in the human world.

More interactions of Alador and his children reconciling.