I almost put down “The Spark” for TLJ but while that’s my favorite musical bit in that movie I don’t think you could call it the movie’s theme. Same with Asteroid Field and ESB.
I also really like The Droid March as it was heard in Attack of the Clones. That piece could have been the PT’s “Imperial March” - I guess it kind of is, but it could have been MORE so. But that would have necessitated writing the droid army completely differently, I think.