Rhystic Study

Search your library for a blue instant card, reveal that card, put it into your hand, then shuffle.

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

XUR, T: Nin deals X damage to target creature. That creature's controller draws X cards.

T: Add one mana of any color in your commander's color identity. Sacrifice this artifact: Draw a card.

Until your next turn, your life total can't change and you gain protection from everything. All permanents you control phase out. (While they're phased out, they're treated as though they don't exist. They phase in before you untap during your untap step.) Exile Teferi's Protection.

Other Merfolk get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)

Exile a creature you control: Add X mana of any one color, where X is 1 plus the exiled creature's mana value. Spend this mana only to cast creature spells.