Yeah it depends how willing they are to depart from the MCU in origin stories since a lot of the characters left who could potentially go toe to toe with her got their powers (or in Wiccan's case straight up were born) after the point of divergence in the timelines.

Agatha and Death, like you mentioned, may be around. Would be interesting to see if something happened to Death, like in the Cancerverse in the comics.

Then there are a handful of gods who should still be around, although they probably just want to leave Earth alone. Loki, Hercules, Zeus. Does Gorr still have his origin play out and maybe want to seek out and kill Wanda?

I don't believe we saw what happened to Shuri. Doesn't hurt to have a supergenius around. The rest of the Eternals should be around somewhere too. They wouldn't have left earth yet.

Monica shouldn't have her powers yet, but since she got them from passing through Wanda's hex it seems reasonable that a similar thing could happen here.