Ylissia, Advent Librarian

{w/u}{u/r}{t}, Discard a card and mill two cards:
Return target instant or sorcery from your
graveyard to your hand.
Delirium — If there are four or more card types
in your graveyard.
Play with the top card of your library revealed.
You may play the top card of your library.
"Soon the yearly celebration begins, sooner the next students arrives."