Ioun, The Knowing Mistress

When Ioun, The Knowing Mistress is put into the
graveyard or exile from anywhere, you may put it
into your library fourth from the top.
You may look at the top of your library at any time,
and you have no maximum hand size.
You can play lands from the top of your library,
and you may cast spells from the top of your library
by discarding a card that shares the a color with
that spell instead of paying its mana cost.