Deep Magic Volume 2 (p.198)
Magnify Weapon
2-level Transmutation
Casting Time: 1 bonus action
Range/Area: Self
Components: Verbal
Duration: 1 minute
Damage/Effect: Buff
The first time you hit with a melee weapon attack before this spell ends, your weapon grows larger just before impact and deals one additional die of its damage. Then your weapon returns to its normal size, and the spell ends.
At higher levels: When you cast this spell using a spell slot of 3rd level or higher, you can magnify your weapon for one additional hit before the spell ends for each slot level above 2nd.
Available for: Bard, Cleric, Paladin, Ranger