Reverie/Wano obv.

Elbaf - but is this the right place for it? I was re-reading and it's nuts to think that back as far as Little Garden, one of the giants said he had an Eternal Pose pointed to Elbaf.

Vegapunk? I could see an entire arc set in Vegapunk's lab/area. And I really dunno if he'll be an ally or enemy. (Side note, I have major theories on a plot triangle between Vegapunk, Kuma, and Franky. Comment if you want to hear more)

Moon? (ENEL?) Are the Strawhats going to space? Is this going to be an arc?

Raftel Arc? Could this be the final showdown of Strawhats/Blackbeard/Admirals/Gorosei?

Will of D Arc? - I'm getting more nebulous now. But part of me wonders if an arc eventually will not center on where, but who. Perhaps 65 chapters occur because several fleets happen to meet at the same point on the Grand Line, and all action occurs between the ships. Maybe we'll get an arc where fate sort of guides certain players together and we get the unassuming "D" children together in the same place.