I think it would be fun if the Rigellians from the Thor Comics of the 60's/70's appear in a future Thor sequel. It would be awesome to see Thor have adventures in the far reaches of the galaxy or in other galaxies with the Rigellians.
In fact it would be awesome if there were a Thor sequel based on a Thor comic book story arc from 1973 featured in issues 218-220 where Thor and the Rigellians battle the five Black Stars which are 5 runaway killer planets from another galaxy orbited by a rogue star that can travel intergalactic distances through space warps and can conquer whole galaxies and entire planets. The Black Stars are controlled by an integalactic race called the Rhunnians who are from an unknown galaxy. That would make an awesome Thor sequel movie in the future.