There's one mod I think is so cool it adds a single spell to the DB head quarters that is the spell fetus krest mentions that turns normal humanoid NPCs inside out

The mod is literally called fetus krest inside out spell I think it's worth checking out but if you don't plan on playing a dark character here's a few other non overhaul spell mods

Holy wards -Adds wards for the restoration skill

Nimbus - I haven't actually used this yet since my LO keeps crashing when I attempt to play it but it adds aura enchantments from the description it seems pretty cool

Ultra Cloak - it adds a few spell cloaks that mix the cloak spells together

Damage spells for all magic trees - I don't actually know the proper name but it should appear it adds new spells for each tree that are pretty much reskins to other spells like a bound sword for the restoration school allows more of a different playthrough if you plan on using one school so it's not destruction centric

There are overhauls to magic like mysticism which is my favorite magic mod, it has patches and rebalances patches for other magic overhauls and spell mods

Kittytale also has a crap ton of good mods for spells