So I'm thinking about systems / settings in the vein of Mage the Awakening, Mage the Ascension, GURPS Ritual Path Magic, GURPS Thaumaturgy, GURPS Cabal, Unknown Armies, or Dresden Files RPG Magic. Here are some of the common characteristics of those systems.
1. Magic is sort of free-form. Instead of having a short list of specific powers, the mage can create whatever effect they want as limited by their skill, tradition, and trapping for the setting (e.g., no bolts of lightning, flashy magic).
2. More powerful / complex magic (more effects, stronger effects) is harder and more dangerous.
3. Spellcasting takes time. Spending more time reduces the risk and danger and vice versa.
4. Spellcasting takes "ingredients" (e.g., magic circles, incantations, symbolic links to the target, sacrifice). Casting w/ (more) ingredients reduces the risk and danger, and vice versa.
5. Casting involves risk and danger. More powerful workings, or workings without reducing the difficulty as above, expose the caster to that risk. That risk could be physical, spiritual, or consequential (bad luck).