I have no idea how you will narrow this down! They are all glorious!
Thistle, I don't know how it is for other people, but ponyhair and calfhair, in person, have a beautiful, sleek sort of sheen, not unlike - dare I say it? - seal. It has a rich, luxurious look that just steals my heart every time.
In an age where even vintage fur gets you jeered at and booed, calfhair and ponyhair are among the last remaining luxury fur-type textiles out there. Beautiful, and for some reason, still socially acceptable.