These are the mounts that are now unobtainable. Meaning that you can NOT get them in the game anymore. These are mounts that used to drop or be rewarded through achievements and quests, but have since been removed from the game.
WoW TCG is short for World of Warcraft Trading Card Game. WoW TCG cards are collectible cards that players can use to battle against each other outside of the game. It uses a card-game style, and can in many ways be similar to Blizzard’s new game Hearthstone. Players can buy these packs in stores and they sometimes contain codes players can redeem for in-game loot. These are the available mounts you can get.
The gladiator mounts are given as a reward to the top 0,5% players in every region, each season. These mounts are rewarded alongside the Gladiator title (Not to be mistaken with the Rank one gladiator titles). These mounts vary from season to season.