I have some buddies who have all of their most used patterns memorized. Ask them what they use for a tail and without hesitation they will tell you their favorite material plus three other options. Unfortunately, I do not share their talent for being an on-demand tying resource. I am constantly pulling out old books, looking up patterns, or going to videos for reference. So to make life easy for myself and hopefully some others, I am going to include resource links here to make finding those references easy.
Bead Head Soft Hackle Pheasant Tail
Holy Grail Caddis Émerger Soft Hackle