This list seems like weaker speculation and is based on the premise that the above list is true and even then it doesn’t have the same parent structure as the Dungeon List. However, these were added in Patch 10.1.5.
Assuming these are also related and we take the Asset IDs of these lines and treat them as Mount IDs, here are the list of mounts that we get:
It’s basically old dungeon mounts. If it doesn’t drop from a dungeon, it’s not on the list.
If you have all that’s on the list, you use the item and it does nothing. But you can still give it to someone else. (that’s what a WoWhead comment said).
I actually got this the other day, and got the Mummified Raptor. A mount that I farmed during BFA for over a 100 runs. Yay? For about 2 minutes. Would have preferred getting it from King’s Rest, rather than from a welfare item. It kind of killed the enjoyment of having the mount.
Anyway seems to be a fair regular drop rate. We had 2 drop once.
The raid mounts look like they belong to the timewalking raid caches added in 10.1.5, though if that’s the case the list is missing Ashes and Invincible, and probably a few cata mounts.
The courser? No I don’t think so. The raid mounts are from the raid quest of the weekly timewalking events (though at a low chance of about 2-3% it seems). I personally got Mimiron’s Head from such a cache. If you stay in a raid after people turn in the quest you sometimes get to see people getting Ashes/Invincible before they leave the raid.
Of course you can only get mounts from the same expansion as the ongoing event.