Have

Loxodon Gatekeeper

Artifacts, creatures, and lands your opponents control enter tapped.

Don't Have

Sol Ring

Kambal, Consul of Allocation

Whenever an opponent casts a noncreature spell, that player loses 2 life and you gain 2 life.

Agent of Masks

At the beginning of your upkeep, each opponent loses 1 life. You gain life equal to the life lost this way.

Platinum Angel

Flying
You can't lose the game and your opponents can't win the game.

Massacre Girl, Known Killer

Menace
Creatures you control have wither. (They deal damage to creatures in the form of -1/-1 counters.)
Whenever a creature an opponent controls dies, if its toughness was less than 1, draw a card.