Regular, meaning Sanke? If it holds liquid with no leaks and sits upright on a burner, it could still be used as a boil kettle or HLT. It doesn't have to be pretty to be useful.
Aging or fermentor if you just want to buy a bung and be done. Could turn it into a holding tank for RO water or a Brite tank if you want to do some welding. Cut off the top and turn it into a pot for growing some flowers...
Or make them into a vessel to hold sanitizer or pbw on demand. I have seen commercial versions from sabco for a Brite tank and yeast bank out of 1/2 barrels. Not to make one as fancy but could be ideas if you feel like having a house yeast or something like that.