Been reading some fantasy lately and I think any wizard worth his salt should know this spell.
4th Level Evocation
Casting Time: 1 action
While not the most powerful spell, this spell is the most utilitarian in a wizards arsenal; this spell may be cast when your hands are bound, and you can only whisper. The spell does 4d6 force damage to anything that is currently touching your hands.
At higher Levels: When you cast this spell using a spell slot of 4th level or higher, the damage increase by 1d6 for each level above 4th.