In Dungeon World, in the Alternative Playbooks, for the Mage specifically, there is the elemental tag. What use is it and what does it do?
The Elemental tag is documented in a later section on the artificer's gear. It means the attack has significant elemental fallout - it can light things on fire, create a crust of ice, throw off lightning bolts, scatter shards, play hob with time, whatever elemental properties you and the GM decide are available and appropriate.
This has no necessary mechanical rider but can change the "meaning" of a Black Magic attack. For example, Winter, Storm, and Dragon Mages have obvious elemental Affinities, so using Black Magic with that elemental tag will benefit from the minimum bonus.
The DM can also say things like
The ogre's charging at you fast, Wizzrobe. Unless this is a frost bolt she's going to run you over.
7-9 on that flame dart and you'll put someone in a spot, huh? Wasn't Shanksworth hiding in that haystack?
The control lever snaps off and slips from Fightgar's grip. Now the only chance to stop this mad machine is to overload its heart gearbox. So tell me, Wizzrobe, how's your aim with a lightning arc?
to show a downside of an elemental tag, or offer a Mage an opportunity to use an elemental tag to accomplish or avoid something they couldn't otherwise.