I don't much like forced gladiator plots and haven't seen Thor: Ragnarok or gotten comprehensive spoilers, yet I'm trying to work it into my heroic Loki AU

I think it'd be between TDW and Ragnarok, but not part of Ragnarok. it'd start when Loki, off traipsing the universe to stay ahead of Thanos and find out about Infinity Gems, comes across the Sakaar Arena and recognizes Hulk

unable to really do anything about that himself, he sends a message to Thor along the lines of "found a friend of yours, think he could use your help" and a location

Thor heads there not expecting trouble and gets captured, which Loki is both amused and frustrated by

Loki sneaks into the gladiator quarters to plot with Thor as soon as he safely can and they get into a brotherly argument over whose fault this is before actually planning the rescue

then... I might need to see the movie, but I'm picturing Loki persuading the Grandmaster to set Thor and Hulk against each other and pretending he's very interested in seeing them fight because he's not on good terms with Thor

(because in the AU he cultivates a villainous wild card image to make it easier to get close to Asgard's enemies so he can undermine them)

Definitely see the movie. I think you could work with it and put in what you like!

probably not gonna see it until DVD rips get uploaded

no running gag of Thor throwing things at Loki to see if he's real, tho. 'cause he doesn't feel like he needs to. if Loki's using an illusion, then Thor trusts that he probably has a good reason, and it'll help Loki keep up his "I'm ttly not with Asgard anymore" cover if Thor's tricked

(Thor trusts Loki is a big theme of the AU. it also helps keep Loki honest, because he's a sucker for Thor approval and respect of his tricks)