Your favorite magic system

[schneeland]

I also enjoyed the Ars Magica system, but since it was not mentioned, I want to add: Shadowrun (I have mostly played 2e, so maybe newer editions change things).
You have dedicated spells, and you can cast them at a force level F (basically as in D&D5, where you cast at the minimum or at a higher level), and then you have to face the repercussions of wiedling magical energy, i.e. mechanics-wise you do a resistance roll against F/2, with damage going first to your mental damage track, then to your physical damage track.
I like this approach for multiple reasons:

1. It has a clear metaphor what happens in the fiction (you channel magical energy through your body)
2. It supports the fiction of exhausting yourself through spellcasting (as e.g. Raistlin in Dragonlance) and even getting a bleeding nose if you wield magical energy above your limits
3. Gameplay-wise it provides a risk-reward mechanic allowing interesting tactical decisions in action scenes.

 

[TwoSix]

I definitely have a thing for magic systems where the different types of magic are codified into a bunch of discrete groupings, and individual characters only have access to a few specific types.

All the various version of M:tA's Sphere system is probably the best example. I also like the Spheres of Power system for PF and 5e, where magic is divided into 20 distinct special abilities (spheres), and characters gain more proficiency and special talents within those spheres as they level.

I'm also a fan of Shadow of the Demon Lord's system with 40+ unique traditions, all of which have about a dozen spells. You can gain low level access to several traditions, or high level access to only a few.

Beyond the Wall's cantrip/daily spell/ritual division is also a lot of fun for a lower-powered game.

 

[Umbran]

Mage: the Ascension's magic system is my all-time favorite, but it only runs well with the right players and GM.

I've a soft spot of Shadowrun's spell and drain system. Upcasting for more effect can have repercussions.

 

[Sacrosanct]

I've a soft spot of Shadowrun's spell and drain system. Upcasting for more effect can have repercussions.

I'm a fan of being able to overcharge spells at a cost. I find it lends to some great thematic situations.

 

[Ath-kethin]

System overall, as in how the mechanics of magic operate in the game? DCC RPG, easy. I'm not a fan of magic being a reliable 'technology,' and DCC has a system in which your magic does SOMETHING at least most of the time, but it doesn't always do what you expect. This approach helps quell any "magic can just solve everything" type thinking.

That said, I also like freeform systems that allow players to concoct their own effects. Stuff like the classic World of Darkness system (though I admit I'm not familiar with any of the books published past 1998 or so).

But I also like magic that is truly specialized, wherein a caster has access to a limited number of thematically linked spells but is REALLY good at using them. Something like the system in Astonishing Swordsmen and Sorcerers of Hyperboria, where each magic specialization, like Cryomancer or Illusionist, is its own subclass, but unlike in 5e they can't both just cast Fireball anyway because it's the easiest way to clear the room of goblins.

For a consistently-reliable magic system, that's my choice.

 

[Ralif Redhammer]

All the various version of M:tA's Sphere system is probably the best example.

Cosigned. It's a great balance between structure and creativity. Back in the day I was probably too strict with Paradox, though.

DCC RPG's spell system is absolutely up there for me as well. Spellburn, Corruption, Patrons, the unpredictability of results. I kinda wish you didn't need a separate table for each spell, but on the whole it's a lot of fun.

 

[Darth Solo]

Depends on the group: if we're going rules-lite, Barbarians of Lemuria has a very freeform system of magic that allows players to make up their own spells. It's very creative while also being balanced by what the spell can actually do. With a group looking for a more in-depth approach to magic, The Riddle of Steel has a system that's powerful but also dangerous, especially for casters as using magic literally causes them to age faster than normal.

 

[kigmatzomat]

Earthdawn is my favorite crunchy system. They took all the OD&D tropes and warped the universe to make it coherent, then leaned into the crazy setting. Casters have to choose spells in advance, the spells can get more powerful by spending more time and/or taking damage, plus they had attuned and leveled magic items. A key thing in Earthdawn is heroes never being touched by an enemy but still near death's door from spending strain.

Shadowrun is a close second. It's not as complex as Earthdawn but aside from mages bleeding out the ears from drain, you have them using the equivalent of mage hand to drop grenades in their enemies laps.

 

[James Gasik]

Earthdawn. At-Will spells but in a very limited number at a given moment; possible to swap out as necessary in the moment, but difficult...or you can just cast from your Grimoire and risk getting your soul ripped apart by eldritch horrors. Great fun!

Plus with four different spellcasting traditions!

 

[doctorbadwolf]

I'm a fan of being able to overcharge spells at a cost. I find it lends to some great thematic situations.

Same.

My own game has 12 magic skills, each with 3 specialties, and each one is a sort of open ended physics engine, rather than having extensive rules. It describes a the type of thing you can do without spending attribute points, and what costs attribute points, in fairly vague terms.

The base resolution system (d12+Xd6 rank dice, success ladder) handles most of the rest of what you need, with player and GM moving the system forward by doing things.

So you can throw a fireball because you’re good at pyromancy, but if you’re level 1 you’ve only got so many, and making a spell bigger, have greater range,Bmaking it hit harder, and making it stick (harder to mitigate the damage), all raise the cost. And you use attribute points for saving bad rolls, as well.