Morophon, the Boundless
From Modern Horizons 3 Commander set
Morophon, the Boundless
Legendary Creature — Shapeshifter
6/6
Changeling (This card is every creature type.)
As Morophon enters, choose a creature type.
Spells of the chosen type you cast cost less to cast. This effect reduces only the amount of colored mana you pay.
Other creatures you control of the chosen type get +1/+1.