Mana Crypt

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

Flying Whenever one or more Pirates you control deal damage to your opponents, you create a Treasure token for each opponent dealt damage. (It's an artifact with "T, Sacrifice this token: Add one mana of any color.") Partner (You can have two commanders if both have partner.)

Whenever a nontoken creature is put into your graveyard from the battlefield, if this card is in your graveyard, create a 2/2 black Zombie creature token. When a creature is put into an opponent's graveyard from the battlefield, if this card is in your graveyard, exile this card.

Flying Each creature you control is a Vampire in addition to its other creature types and has "Whenever this creature deals damage to a creature, put a +1/+1 counter on this creature."

At the beginning of your upkeep, flip a coin. If you lose the flip, this artifact deals 3 damage to you. T: Add CC.

Exile target creature. Its controller gains life equal to its power.

Whenever another creature you control dies, create a Treasure token. (It's an artifact with "T, Sacrifice this token: Add one mana of any color.")

Menace Whenever one or more Pirates you control deal damage to your opponents, exile the top card of each of those opponents' libraries. You may play those cards this turn, and you may spend mana as though it were mana of any color to cast those spells. Partner (You can have two commanders if both have partner.)