I was not as big a fan of harvest because it felt kind of limited. It's not as broad as gathering, which could incorporate concepts such as a hidden object game gathering all the items you need for a trip. Or a story game about gathering your friends together for a party. So what's the difference between harvesting and gathering? In the most general sense, I think harvesting is gathering items for consumption directly from the source. Picking apples at an orchard would be harvesting, but buying them from the grocery store would not because they've already been harvested. There might be some exceptions to this, but it's the best rule of thumb I could think of.

In that vein, some possible things to harvest beyond crops could be minerals, souls or magic energy. Much as Harvest is more limited than some other themes, I think there are still a lot of unique possibilities.

Good luck to everyone in the jam!