In an earlier post, I mentioned along with a couple of other ideas some different fuels that could be added to Unturned 4.X. Air rifles, propane, and fuel The other ideas I had were discussed, but not the fuels, so I would like to expand on those ideas here.
Wood, Charcoal, paper, books, and coal could be used in campfires, stoves, grills, and perhaps antique trains, power stations, antique ships and steam engines. Wood would be acquired mainly from the wilderness. Charcoal would be found in campsites, and civilian locations, and perhaps crafted. Paper and books would be found in libraries and office buildings. Coal could be found in industrial locations.
Propane would be used in grills, ovens, generators, lamps, and certain weapons. Propane cans (the dark green head sized ones) would be found at campsites. Propane tanks (the white torso sized ones) would be found at gas stations.
Gasoline would be much the same as in 3.X, although hopefully it would be harder to get usable gasoline from the ground.
Diesel (which would also serve as jet fuel and napalm) would be used in heavy vehicles, and generators, and perhaps flamethrowers. It would be found at gas stations, airports, and/or military locations, depending on the map, and what vehicles are available on that map.