Draconic Essence. Depending on the color of the dragonling it has resistance to a specific damage type.

Trampling Charge. If the dragonling moves at least 20 feet straight toward a creature and then hits it with an attack on the same turn, that target must succeed on a DC 14 Strength saving throw or be knocked prone. 

Multiattack. The dragonling attacks twice, once with its bite and once with its tail.

Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one creature. Hit: 8 (1d8 + 4) piercing damage.

Tail. Melee Weapon Attack: +6 to hit, reach 5 ft., one creature. Hit: 7 (1d6 + 4) bludgeoning damage.

Trusted Mount. While the dragonling is used as a mount, whenever the rider is attacked, the dragonling can use its reaction to make a bite or tail attack against the attacker.