Shifter - I think these exist in 5e, but they had a much higher profile in 4e, IIRC. Werewolf-lite. Probably need to be MORE Werewolf to really catch on.
For the record, Shifters are one of the new races from Eberron. They started in the 3e campaign book and appear again in Eberron: Rising from the Last War in 5e before going to MotM. The other Eberron original races are Changelings, Kalashtar, and Warforged. Of those four, I actually think Changelings are the most successful.
Kalashtar are generically pretty human-alikes, psionic, and deeply rooted in Eberron specific lore. Which is three strikes against them. Warforged are a bit divisive with the "magic robots" thing, and are also somewhat rooted in Eberron lore. Two strikes, and you'll note neither appeared in MotM. Meanwhile Shifters did appear in MotM, but their problem is they're not furry enough for the anthro enthusiasts and too furry for the anthro avoiders. They've never really caught fire.
Changlings, though, have potential. Shapeshifting is fun, and they've got a lot of appeal for players who want a character with a more fluid identity, along any of several axis. Also their lore is flexible enough they're easy to place into most settings. They're still a mid tier pick, not yet ready for the PHB, but I think they're near the top of the MotM batch.