10 Supporting MCU Characters That Must Appear In The Disney Plus Series
7. Sif
Thor's supporting cast prior to Ragnarok wasn't that interesting, but one character that could do with returning is Sif.
After being absent from the third Asgardian epic, as well as Infinity War and Endgame, having the warrior return would help explain where she was during those major events, because her missing such a crisis surely has to have an interesting in-universe explanation (as opposed to it simply being a scheduling issue for Jaime Alexander).
Much like with Hank Pym, the time travel antics that seem to be happening in Loki would make it easy for Sif to slot into that series, whether that be a version of the character from before Ragnarok or preferably after it.
If Darcy can return, then Sif sure as hell can.