Homebrew
Innate Spellcaster. This dragon can innately cast two spells, once per day each, requiring no material components. Each spell's level can be no higher than 2nd. The dragon's spell save DC is DC 13, and it has +5 to hit with spell attacks.
Evil. The dragon radiates an Evil aura. Sunlight Sensitivity. While in sunlight, the necrotic dragon has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.
Multiattack. The dragon makes three attacks: one with its bite and two with its claws. Bite. Melee Weapon Attack: +7 to hit, reach 1 sq., one target. Hit: 15 ( 2d10+4 ) piercing damage plus 4 ( 1d8 ) necrotic damage. Claw. Melee Weapon Attack: +7 to hit, reach 1 sq., one target. Hit: 11 ( 2d6+4 ) slashing damage. Anguished Breath (Recharge 1d6>=5 ). The dragon exhales a shadowy maelstrom of anguish in a 6-square cone. Each creature in that area makes a DC 14 Wisdom saving throw, taking 49 ( 11d8 ) necrotic damage on a failed save or half damage on a success.
The Underdark