Angela

Simply put it, Angela is literally an Angel – a bounty hunter that could easily be a part of the ragtag team in Guardians of the Galaxy 2. Not an actual member of the team in the comics, she has appeared with them on several occasions.

Of course, it can be said in here that she was later revealed that she is the secret daughter of Odin, thus making her the sister of the God of Thunder – and like Thor himself, she too finds herself tricked by Loki.

Of course, the connection with the rest of the MCU is pretty obvious and either Thor or Loki could make an appearance in Guardians of the Galaxy 2. Or maybe it will be the other way around, since Thor: Ragnarok will be released about 6 months later. And since Ragnarok will be a cosmic event, the Guardians might fit in pretty well (also, it can be noted that Chris Pratt said that he will appear in another Marvel film besides the Guardians franchise and besides the Infinity War).