Om du inte letar efter en synonym / alternativ, tycker jag att "magisk effekt" själv är lämplig - det täcker både stava och icke-stavningsfall. Dessutom hänvisar flera spelelement (i 5e, åtminstone) till dem som sådana:
Choose one creature, object, or magical effect within range. [...]
Spells and other magical effects, except those created by an artifact or a deity, are suppressed in the sphere.
[...]
Spells and other magical effects, such as magic missile and charm person, that target a creature or an object in the sphere have no effect on that target.
Nystul / Arcanists Magic Aura:
You change the way the target appears to spells and magical effects [...]