it would be really cool if there was "elemental magic" but for like. the periodic table of elements lol
also if people could only specialise in a couple of different elements and some people luck out and get carbon but other people end up with like. lutetium or some obscure shit
what if people didn't know about the different elements, like how we didn't in the past? so you'd get kids whose parents were "only" air elementals (hydrogen + oxygen) who have no idea how they ended up with water powers.