Commander creatures you own have "Whenever this creature becomes tapped, it and other creatures you control that share a creature type with it each get +2/+0 and gain undying until end of turn." (When a creature with undying dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Black creature spells you cast cost {1} less to cast. Whenever you cast a creature spell, each opponent loses 1 life and you gain 1 life.

{T}: Choose any number of target creatures. Each of those creatures gains persist until end of turn. (When it dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Creatures you control are every creature type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield. {3}, {T}: Create a 2/2 blue Shapeshifter creature token with changeling. (It is every creature type.)

Equipped creature gets +1/+1 and has haste. At the beginning of each combat, untap equipped creature. Equipped creature has first strike as long as it's blocking or blocked by a Goblin or Orc. Equip {2}

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.) Whenever you tap a Swamp for mana, add an additional {B}.