I’ve personally found great effectiveness using cloud of daggers maybe more than any other spell. Funnelling enemies through a passageway with multiple cloud of daggers cast on the spot is probably my current meta. Then I utilize thunder wave/ black hole to keep the enemies on the other side of the daggers once they make it through.
Another thing if found amazing success with is getting a party to strength 20 as fast as I can, which then I find 90% of enemies can be thrown off cliffs for instant kills. Throwing enemies off cliffs also only requires stealth checks where the body hits the ground and dies.
Lastly there is a fun little cheese strategy I’ve picked up that I don’t see anyone talking about. If you cancel an improvised weapon attack with an NPC before you deal damage, you can move NPC’s without angering anyone.
Keep in mind this is theoretical, so assumes perfect setup + max damage rolls
Hasted sorcerer attacking a grouping of five enemies
action 1: throw a bottle of water at them
action 2: twinned spell Chain Lightning
initial targets hit once, doubled for wet (80x2=160)
each enemy aside from the initial two targets is hit twice, doubled for wet (80x2x3=480)
(very) theoretical max damage of 640 for one spell slot and 6 sorc points
Meta it is not, due to the very specific use-case and the setup required, but it’s a great opener or closer, and I pretty commonly hit +200/250dmg using this. Cleared every single ad in the >!Orin!< fight in one shot this way lol
Another fun build I just tried out in my friend’s game
Paladin/tempest cleric
Moving parts are as follows
Thunderous Smite (spell slot)
utilize Destructive Wrath to ensure max damage roll on the thunder damage (channel divinity - short rest)
use Luck Of The Far Realms to ensure crit (long rest)
use Divine Smite on Crit for more booku bux (spell slot)
Haven’t played w this one too much, for stats you’ll want to dump CHA tho, weird for a paladin build but the important bits of this build don’t involve the actual spell effects for paladin so ¯\_(ツ)_/¯ in terms of efficacy though, at level 7 I did 120 damage in one attack lol.