Let's see what you can come up with

He actually knows what the Cosmic Council is and he's on their watchout list

Collector: oh you have no idea the amount of lists I'm on.

The Traveler: It's because of me you haven't been on the Danger list yet, you should thank me for giving you a good reputation

The Collector goes to hell sometimes to keep Diabolus in check

Collector: pretty close, I have a certain unholy associate who tells me whenever he's close to breaking free.

A certain somebody could speed it up though...

The Traveler: Unfortunately you never knew He broke free, and hey! Part 3 coming out soon

Next headcanon: Collector feels like Xander had to die because he would become too strong be left alive. So when he died the Collector would tell Eggy and some others not to revive Xander so he can't become a super-destroyer

Collector: seems logical.

But I saw him yesterday, Isn't he still alive?

(I thought Xander hasn't canonically died yet)

(He isn't dead yet)

he has stayed on multiple planets trying to be different people during his lifetime, some consider him a hero, celebrity, or even just a cool store clerk

Collector: I have had many professions over the years.

so its cannon?

Sort of

He is secretly obsessed with checking obscure Fandom.com wikis

HE MADE AN ALLIANCE WITH SALTU PLZ PLZ PLZ

Who the heck is saltu

Saltu is the jungle planet that Gingerbread Man rules

Collector: I am neutral with that planet. I don't visit it often but I'd rather not have somebody destroy it.

Eggy and him have a father-son relationship

He Licked A Frozen Pole In Winter

Collector: if I did the pole probably felt more pain than me.