Guild Wars 2

is it any wyvern or just the adult legendaries? im looking to complete the ydalir collection

Any Wyvern mob as well as Wyvern caches (the caches are basically the exact same thing as looting that type of mob, but in container form). Possibly also the “bags of HoT area loot” as well, as I think I’ve gotten at least one of the rare HoT enemy drops from one of those, though they aren’t really something you can grind out or anything so not really a reliable source so much as a potential bonus for doing story missions.

https://wiki.guildwars2.com/wiki/Wyvern_Scale

Should be any wyvern. Keep in mind that these items for collections do tend to be rare drops.

I know I got mine from a “Wyvern Cache” so you could try farming those also