If?........

Thor makes his return at the Rune King, will there be anyone on Marvel earth who can stop him?

Possibly Dr. Strange.

It could also be a good oppurtunity for Marvel to pit Sentry against him so we see just how powerful he really is.

The phoenix 😛

Maybe Black Bolt but that's assuming they would be on alternate sides.

(In honesty I'm not sure if Black Bolt can take him but then again I'm not certain about the extent of BB's power.)

Those are probably about the only ones who could stop him, I mean, seriously, RKT would be stronger than Thanos, and we all know how much success Earth has had when dealing with Thanos (seeing as it's always up to Warlock or someone cosmic).

The most impressive thing imo about Thors new power is his ability to see and know everything.