I've been thinking a lot on the idea of magic systems. I think it pretty cool how different they can be: different rules, if objects are involved, spells, ritual circles, elemental magic, possible religions, and so on! :>
We got a series of books named The Lord of the Ice Garden, where there are spacefaring humans who discover a medieval alien civilization, and there are nanites which can do things that would be described as magic. Idk honestly, I got to read the series properly one day.
When I was little, I created our own Hogwarts-like magic school. We had an interesting magic system - bells were used to summon different spells (of course we didn't use real bells for playing, but it was an interesting concept)