This got me thinking about which Harry Potter spells would suit larp well.
There are some with no visual effects required which seem absolutely perfect for larp. Like Expelliarmus - you’d just throw your wand away. Confundo, Crucio, Petrificus Totalus, Silencio, Stupefy and Obliviate could all be easily acted out by the target. Episkey for healing, Finite Incantatem to dispel magic effects, Protego to reverse them back at the caster. Piertotum Locomotor could be used to bring statues to life, if someone was playing the statue. That’s ten spells - you wouldn’t want too many in the game if you wanted players to remember them all.
As a thought for a magic system, each player could have a list of spells they have mastery of, and can cast as much as they want. They’d also have a list of spells that require effort (either because they haven’t mastered them or because they’re tiring), and each player could have a number of Energy points or something that they can spend to cast those limited-use spells.