Like the All Saints' Wake had the Witch's flying broom, I think a flying reindeer could be good as the Christmas event's mount. For Valentine, Easter, Ladies and Heavensturn... I don't know. For the next Moonfire Faire I would like a new version of the Bomb Palanquin, but for two characters (like in the artwork of the 2015 event, I don't know if it's currently possible, but I've never seen two characters in the same Bomb Palanquin).

Also, in my last thread I've suggested a seasonal event in which we can obtain mounts from previous FF games, like the classic design of the Airship from the original FF, or Cloud's motorbike from FF7 (although this is not a flying mount).

Maybe this is impossible, but a Bismarck mount too. Not a horse like the other Primals, Bismarck itself (smaller of course).