Dragonborn

You have draconic ancestry. Choose one type of dragon from the Draconic Ancestry table. Your breath weapon and damage resistance are determined by the dragon type.

You can use your action to exhale destructive energy. Your draconic ancestry determines the size, shape, and damage type of the exhalation. Each creature in the area must make a saving throw (DC = 8 + CON mod + proficiency bonus). Damage: 2d6 at 1st level, scaling to 3d6 at 6th, 4d6 at 11th, and 5d6 at 16th level. Usable once per short or long rest.

You have resistance to the damage type associated with your draconic ancestry.