DND 5E races

Feral tiefling

While tiefling's have at least some humanoid features Feral tieflings have more devilish look to them as they have longer horns, they may have cat like eyes or a forked tongue. They have fairly long tails and may have goat like legs and hooves.

Traits that come with this race.
Your intel score is increased by 1 point and your dex is increased by 2 points.
You age around the same as humans.
While many feral tieflings are chaotic evil many don't lean towards the evil side but more of the chaotic side since they are still part of the underdark.
You can see 60ft in the dark but only in shades of gray.
You have resistance to fire damage.
You know the cantrip thaumaturgy and know the spells hellish rebuke and darkness.
You can read. Write and speak common and infernal.
Your walk speed is 30ft.

There are really only two subraces/ variants to the tiefling.
Variant tiefling and Variant feral tiefling are fairly similar as they both have the same 3 tiefling variants.

The devils tongue lets you know the cantrip vicious mockery and know the spells charm person and enthrall.

The hellfire lets you cast the spell burning hands

The winged lets you have long black bat like wings and your fly speed is 30ft while your not wearing heavy armor.

All three replace the infernal legacy trait.