What spell(s) are made stronger with pierce?

I'm planning on making an Occultist with four curses on blasphemy. Initially I wanted to make her a fireballer just cause I arbitrarily wanted to shoot fireballs, but I also want projectile weakness as one of my curses which would give my projectiles pierce which I can't imagine would be very good with fireballs. Just wondering what spells would be more suited. Not looking for any meta advice or anything that would drastically change my plans. Also I absolutely do not want to see a full build guide. Cheers.

Long range or fast casting spells work best. Fast casting because it increases the chance of knockback, which is amazing for defence.

Eg. Essence drain gets both knockback and more life regen (from pierce hitting more monsters), so is superb wirh PW.