Outside of dungeons, exploration yields nothing but Gasha Seeds and Rings. These are in Seasons as well, but they felt worse here because they felt like the bulk of the side stuff.
... but Ages goes way too far with this idea. 6/8 of the main dungeons are themed around being a shape, and I'm convinced the only reason the other 2 aren't shaped is because Capcom didn't know how to make "ghost shaped" dungeons.