Elemental Blade

You infuse a melee weapon with elemental energy. Make a melee or thrown attack with the weapon. On a successful hit, deal an additional 1d8 damage of the chosen elemental type, plus your spellcasting modifier. Choose from acid, cold, fire, lightning, poison, or thunder.

At Higher Levels:

The damage increases by an additional 1d8 when you reach 5th level (2d8), 11th level (3d8), and 17th level (4d8).