I really like the sentinels comics rpg - https://www.greaterthangames.com/pages/sentinel-comics
It's based on the sentinels of the multiverse card game, and has a really unique system. Basic low down - every roll you have die based on a "stat", a power, and your (or the scene's) status (green, yellow, red).
On a basic roll, you always take the middle die as your results. Powers might alter this or do something extra.
So for example, let's say you have super strength as a stat for a d8, a power die of a d6 for the power you're using, and a d6 for your current status (green). You'd roll all three of these and take whatever value is the "middle" result (so like d8 - 2, d6 - 4, d6- 5, you'd get a 4).
Powers might do something like "deal damage equal to the lowest die, but heal an ally for the middle die" or "deal damage with the highest die, but take a penalty equal to the lowest die"
Not gonna lie, "magic stealer" is a really bad name. What's wrong with the classic spellthief?