My wish list for the sequel,
Beta Ray Bill - (He could be from a planet that survived the emergence which gives him a link the Eternals story.)
Nova Corps - (Post Thanos, they have become the universe's police, and have kept there eye on any planet destroying incidents)
Galactus - Set up the character maybe post credits.
Silver Surfer - Another character set up. Maybe the first planet Druig and Makkari visit is Zen La.
Norinn Radd is an eternal that has also fallen in love with his planet. Makes the sacrifice to become the herald.
Ravagers - Maybe as a B or C side presence. I've really warmed to them as characters and it would make sense that they would do clean up on any planets that are destroyed as there must be a lot of interesting resource's to "ravage".
I also don't want this movie to spend little to no time on Earth. It really want to Cosmic side of the MCU thoroughly explored.