Haldan, Avid Arcanist

Partner with Pako, Arcane Retriever (When
this creature enters the battlefield, target player
may put Pako into their hand from their library,
then shuffle.)

You may play noncreature cards from exile
with fetch counters on them if you exiled
them, and you may spend mana as though it
were mana of any color to cast those spells.