Ynsed, Compulsive Curator

Whenever one or more cards leave your library without being drawn, put a Lore counter on Ynsed.

At the beginning of each end step, reveal the top card of your library. If it's a nonland card with mana value less than the number of Lore counters on Ynsed, you may cast it without paying its mana cost. Otherwise, shuffle your library.

I know it's here somewhere...