so so many. bladesmithing and all around metal work. electronics. woodworking is my #1. winemaking slash brewing. music(only the classics). absolutely primitive weapons, actually not blades. pyrotechnics, games, stuff and junk.
Fire drying a smelter. Considering ditching oil for charcoal to forge but definitely keeping for smelting. Hippocratic? Yes. But smelting is by far more important to me as forging is a hobby. Smelting billets would help me accomplish other things.