theory11 — Magic Tricks & the World's Finest Playing Cards

Impromtu card magic

Card Control by Arthur Buckley and The Classic Magic of Larry Jennings. Also check out By Forces Unseen.
 
Harry Loryane's Classic Collection Vol 1-2
Most of John Bannon's books are impromptu
Paper Engine
Buck Twins' materials
 
I just picked up "Revelations" by Dai Vernon. Obviously haven't read it yet- but the table of contents alone looks very impressive. The book ran me 65 bucks but it looks so worth the price.