- Magic by metaphysics.
- Magic with a more or less randomized effect based on casting check (DCC, Them deeper bones).
- Magic by creatures (Carcosa, Sorcerer).
- Magic with a fixed effect, from an expansive list that implies engineering arbitrary effects.
- Magic with a fixed effect, from a limited or quirky enough list to make every spell distinctly its own thing.
- Magic with significant consequences or price.
- Magic as GM fiat.
- Magic as narration rights.
- Magic defined as a formal effect, without an obvious necessary fictional interpretation.
Of these, 1, 7 and 8 are highly dependent on the group. Four is clearly engineering magic, whereas 1, 3, 5 and 6 tend to feel more magical. Two and nine depend on the degree and nature of randomization in one case, and on what kind of formal effects there are in the other.