Historically upgrade cards have teased upcoming releases; i.e. Death Troopers, Bossk.
If this is any precedence then Tauntauns are definitely on their way as they are featured on the recently teased “Endurance” card.
The only logical Imperial counterpart to this would be dewbacks. (If you can think of any others, please let me know in the comments below).
Super exciting.
Legion HoloNet