Update when arena gladiator mount comes out
Snowcap Fledgling Gryphon.
Eventually, I was able to purchase my most-desired Dusky Fennec Fox from the Crown Store with 40 gems; however, I am still missing a Snowcap Fledgling Gryphon.
Also, Crown Invisibility Potion x 5.
This set used to be available for 3 gems from the Crown Store, but since has been discontinued and replaced with the Gold Coast Swift Survivor Elixir, which does not confer invisibility, and the Gold Coast Survivor Elixir, which only confers invisibility for 8 seconds vs. the 11.5 seconds of the Crown Invisibility Potion.
Specifically, I need the Crown Invisibility Potion for Thieves Guild heists, which are difficult for a level 36 Sorcerer without it.
@DekuDekuplex Hey there dude. Just saw this post and I immediately thought of the following potion: Roguish Stealth Draught
You can buy these from Guild Traders off other players, or loot them from thief troves around Tamriel.