Kinda realizing that 90% of the spell lists are practically pointless
So here is my list of the only useful spells I've found

Petty Heal- The most necessary magic spell in the game, basically a full health bar for practically nothing.
Every "Wind" type spell- UNLIMITED POWAH, these are the ONLY spells I see any serious offensive use for, not that you NEED much else once you have one.
Dust Storm- thought this was useless until one of my celestial wizards knocked me off my horse with it. Cheap Anti Cav AoE? That's a good'un

Summoning/Necro spells- useful very early, pointless later

AND THAT CONCLUDES THE LIST
Please comment below if you've found uses for other spells, atm I'm thinking the above are the only ones worth saving your winds for.