Pseudodragonborn (5e Race Variant)
From D&D Wiki
Much as one could compare in terms of height a human to a halfling, one could compare the stature of a dragonborn to their pseudodragonborn cousins.
Size. Most pseudodragonborn are about 4 feet tall and weigh about 60 pounds. Your size is Small.
Speed. Your speed is 25 feet.
Breath Weapon. As an action, you can exhale a 15-foot cone of poison. Each creature in the area must make a Dexterity saving throw. The DC for this equals 8 + your Constitution modifier + your proficiency bonus. Creatures that fail the save take 2d6 poison damage and becomes poisoned for 1 minute. If the saving throw fails by 5 or more, the creature also falls unconscious for as long as it is poisoned, or until it takes damage or another creature uses an action to shake it awake. The damage increases to 3d6 at 6th level, 4d6 at 11th level, and 5d6 at 16th level.
After you use your breath weapon, you can't use it again until you finish a short or long rest.
Damage Resistance. You are resistant to poison damage.