Don't really play pvp, but here are my pve faves.

Equus. I enjoy the smoothness of the first person ride and tool-usage so much. It is so easy to control and I love bumping up melee and knocking out anything I want. I never use my Mortar and Pestle anymore either, I just use the Equus saddle. I hope to one day breed them but I have never seen a high level female that wasn't eaten within moments of me spotting it.

Thylacoleo. I would rather use Thylas than fly anymore. I enjoy breeding them for Melee and murdering anything that gets in the way of my joy ride lol.

Yutyrannus. I'm a huge dino feather person but I won't get into that. They're one of my favorite models in the game right now and I breed them for color, mostly. They're just a vanity mount (for me) at this point, but I hope to eventually do boss battles with them.

Ichthyornis. I love this thing. I'm so sorry... I have an addiction to catching them because it's annoying, and recently I got into breeding them. I got my very first color mutation on an Ichthyornis.

Tapejara. Pterosaurs are some of my favorite prehistoric animals and Tapejaras are the ones that delight me the most. The Ark model isn't my favorite but I love their functionality and I at one point had an addiction to catching them just like the Ichthyornis.