Taneleer Tivan aka the Collector is one of the immortal Elders of the Universe. He uses his infinite lifespan collecting all kinds of interesting things as part of his grand collection.
Cosmo The Space Dog
Cosmo is a dog that was subject to Soviet experiments during the Space Race. he was sent to space to test out new rocket technologies but never got back. In outer space, Cosmo was exposed to cosmic radiation that gave him telepathic abilities. In the comics, Cosmo teams up with Nova and later Guardians of the Galaxy as an official member of the group.
Howard The Duck
The dude with the quack has a very loyal fan following even outside comic book fan circles. Howard The Duck had a solo movie featuring him in the Eighties, which no enjoys a cult like following. He was later seen in Endgame in the background, aiding the Avengers in their fight against Thanos.
The Sovereign were a race created specifically for the MCU. Instead of being born naturally, they hatch their own using specialized, custom made cocoons. One of those cocoons ended up hinting at Adam Warlock in GOTG Volume 2. Maybe this was a prototype the Sovereign abandoned?
A Dark Elf
At the end of Thor: The Dark World, the evil race of Dark Elves are defeated and pushed back. The Reality Stone is now in the possession of the Collector. It is entirely possible for him to have a Dark Elf too. The Asgardians must have handed over a Dark Elf POW to the Collector.
No one can forget the dreadful Chitauri and their Leviathan armada in The Battle of New York in The Avengers (2012). The Collector seems to have gotten his hands on a Chitauri foot soldier. This one was certainly not a part of the New York invasion since it is still alive.
This was a fun homage by James Gunn to himself. Slither starred Elizabeth Banks and Nathan Fillion and told the tale of nefarious slug like creatures. These slugs are also within the Collector’s Museum.
A Never Dude from Arrested Development
Arrested Development easter egg in the leaked Avengers: Infinity War clip. A reference to Tobias Fünke after he auditioned for the Blue Man Group. pic.twitter.com/lyVi3NJ9Oh
— GuruKid (@FunWithGuru) November 26, 2017
In the legendary sitcom, Tobia Funke plays the Never Dude, who refuses to be naked. So he wears jean shorts as a fix. He even auditions for the Blue Man group after covering his entire body in blue paint. A Never Dude who looks just like Funke’s character is within one of the pods in the Collector’s Collection.
A Frost Giant
The Collector also has a Frost Giant from Jotunheim in his collection. The features are hard to make out but that is him.
The Reality Stone
The Asgardians deliver the Aether to the Collector for safe-keeping after the events of The Dark World. Thanos later destroys the Collector’s museum and takes it for himself.
The Collector had two Kylorians, one was imprisoned for not being efficient enough. The other, named Karina, killed herself by touching the Power Stone. Peter Quill’s romantic interest Bereet and John C Reilly‘s character’s wife in GOTG Volume 1 are also Kylorians.
A race very commonly seen in GOTG Volume 2 (Arago-7) and in Xandar in GOTG Volume 1 (Xandar).
A NASA Astronaut Suit
Cosmo the Space Dog is not the only artefact from Earth in the Collector’s collection. He also seems to have a fully operational NASA Spacesuit in his inventory.
Xeronians are peaceful creatures that abhor violence. The Xeronian race is a part of Thor: The Dark World. In the comics, the King of Xeronians battled the Hulk after absorbing huge amounts of solar radiation.
This alien has no reference or connection to Marvel Comics. It looks to be a reference to Guillermo del Toro’s Hellboy. James Gunn is a fan of del Toro’s works.
A Giant Butterfly
This too has no connection to Marvel Comics. The Butterfly could be a reference to Mothra from Godzilla: King of the Monsters, a movie that early rumors claimed James Gunn was going to be a part of.
Giant amoeba like creatures with tentacles for arms, they are a staple in many Thor comics.
A tall, slender alien is also seen in the background in one of the scenes. We believe it is a Poppupian, a race Marvel superhero Impossible Man hails from.
Beta Ray Bill?
— James Gunn (@JamesGunn) November 17, 2014
There was actually a Beta Ray Bill reference in the MCU before we saw the Korbinite Champion’s face on the Grandmatser’s Tower on Sakaar in Thor: Ragnarok. Many believe Beta Ray Bill, the last of the Korbinites, was imprisoned by the Collector before he was freed after the explosion in GOTG Volume 1. Does this mean Beta Ray Bill is now out there in the MCU?
Jury’s still out on this one. Since the Collector got his hands on a NASA spacesuit and an Earth dog, it is entirely possible he even managed to plunder the wrecked Destroyer armor after the events of the first Thor movie. Or it could be the Collector’s Etherion armor, a battle armor he wears in the comic books.