Children of Korlis

Sacrifice Children of Korlis: You gain life equal to the life you've lost this turn. (Damage causes loss of life.)

Rhox Faithmender

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
If you would gain life, you gain twice that much life instead.

Tree of Redemption

Defender
{T}: Exchange your life total with Tree of Redemption's toughness.

Yavimaya, Cradle of Growth

Each land is a Forest in addition to its other land types.

Tainted Sigil

{T}, Sacrifice Tainted Sigil: You gain life equal to the total life lost by all players this turn. (Damage causes loss of life.)

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

Fumigate

Destroy all creatures. You gain 1 life for each creature destroyed this way.

Exquisite Blood

Whenever an opponent loses life, you gain that much life.

Gollum, Obsessed Stalker

Skulk (This creature can't be blocked by creatures with greater power.)
At the beginning of your end step, each opponent dealt combat damage this game by a creature named Gollum, Obsessed Stalker loses life equal to the amount of life you gained this turn.