I have created some new cantrips which include making a weapon attack as there are only two official ones to choose from. I've tried to follow these principles based on Booming Blade and Green-Flame Blade:
- Melee weapon attack only, 5 foot range
- No unavoidable extra damage to the primary target at level 1
- Damage no more than 2 targets
- Spellcasting ability modifier doesn't have to affect the spell at all
- Only available on the Warlock, Sorcerer and Wizard spell lists
But with such a small amount of official content to compare them against, it's hard to say if they're balanced.
Is this spell balanced with Booming Blade and Green-Flame Blade?
Blade of Hate
Casting Time: 1 action
Range: 5 feet
Components: V, M (a weapon)
Duration: 1 round
As part of the action used to cast this spell, you must make a melee attack with a weapon against one creature within the spell's range, otherwise the spell fails.
On a hit, the target suffers the attack's normal effects, and it must make a Wisdom saving throw or become afflicted with an irrational hatred of you until the start your next turn. On its turn, it must use its action to attack you or include you as a target of or in the area of a hostile ability if it can. (Other targets may be chosen as well as you if applicable). Undead and creatures immune to being Charmed aren't affected by this effect.
At 5th level, the attack deals an extra 1d6 psychic damage to the target. The damage roll increases by 1d6 at 11th level and 17th level.