Are you wanting an addon that only wants Dragonriding ONLY mounts ( the ones you can ONLY get in Dragonflight zone ) in a random shuffle or dynamic flight able mounts ?
The changes Blizzard are implementing ( some already done ) is the ability to turn on and off the dynamic flight ability for other mounts and not just the dragonriding dragons we initially started with in Dragonflight.
For example: Some of the old world dragons will have the ability to use dynamic flight ( dragonriding ) and old school flight (able to stop midflight ).
And they plan to expand the ability to other flying mounts that aren't able to immediately utilise the dynamic flight system due to their visual makeup ( such as the magic carpet ).
Looking at the MountJournal API
https://warcraft.wiki.gg/wiki/API_C_...tMountInfoByID
They added isForDragonriding variable to the return values. This would likely be added to the other mounts once they have been set up to work with the dragonriding system.