Here is a list of new mounts that should be looked into and potentially added. I have gone over the full list and filtered out irrelevant items.
Note that some of these are still missing accurate drop rates.

• Verdant Skitterfly Prerequisite: Renown 25 with Dragonscale Expedition. Source is available before getting the required renown, so needs to take this into account (#532)
• Reins of the Liberated Slyvern (#521)
• Plainswalker Bearer (#521)

Looking into the Skitterfly mount, it seems to require looting yet another object from the ground.

As for the renown check, I think this might work:

• C_MajorFactions.GetMajorFactionIDs to find the right ID
• C_MajorFactions.GetCurrentRenownLevel to check the renown level

So far that's completely untested (I don't even have DF), but it should be easy enough to manually verify ingame.

excluding renown, is the verdant skitterfly similar to the spectral mawrat's tail from shadowlands?

excluding renown, is the verdant skitterfly similar to the spectral mawrat's tail from shadowlands?

I can't say for sure, but if it's an object lootable from a container on the ground then yes - it should use the same method.

used the same method and it works for every expedition scout pack looted regardless of renown, just got to add the renown check now.