Sanguine Bond

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

Peregrin Took

If one or more tokens would be created under your control, those tokens plus an additional Food token are created instead. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
Sacrifice three Foods: Draw a card.

Frodo, Adventurous Hobbit

Partner with Sam, Loyal Attendant
Vigilance
Whenever Frodo attacks, if you gained 3 or more life this turn, the Ring tempts you. Then if Frodo is your Ring-bearer and the Ring has tempted you two or more times this game, draw a card.

Battle at the Bridge

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Target creature gets -X/-X until end of turn. You gain X life.

Plains

Abzan Battle Priest

Outlast {W} ({W}, {T}: Put a +1/+1 counter on this creature. Outlast only as a sorcery.)
Each creature you control with a +1/+1 counter on it has lifelink.

Took Reaper

When this creature dies, the Ring tempts you.

Ivory Cup

Whenever a player casts a white spell, you may pay {1}. If you do, you gain 1 life.

Ajani's Welcome

Whenever a creature you control enters, you gain 1 life.

Vizkopa Confessor

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.)
When this creature enters, pay any amount of life. Target opponent reveals that many cards from their hand. You choose one of them and exile it.

Setessan Battle Priest

Heroic — Whenever you cast a spell that targets this creature, you gain 2 life.

Soul Charmer

Whenever this creature deals combat damage to a creature, you gain 2 life unless that creature's controller pays {2}.

Abzan Kin-Guard

This creature has lifelink as long as you control a white or black permanent.

Rhox Bodyguard

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
When this creature enters, you gain 3 life.

Dragon's Claw

Whenever a player casts a red spell, you may gain 1 life.

Greater Tanuki

Trample
Channel — {2}{G}, Discard this card: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Swamp

Bilbo, Birthday Celebrant

If you would gain life, you gain that much life plus 1 instead.
{2}{W}{B}{G}, {T}, Exile Bilbo: Search your library for any number of creature cards, put them onto the battlefield, then shuffle. Activate only if you have 111 or more life.

Cleric Class

(Gain the next level as a sorcery to add its ability.)
If you would gain life, you gain that much life plus 1 instead.
{3}{W}: Level 2
Whenever you gain life, put a +1/+1 counter on target creature you control.
{4}{W}: Level 3
When this Class becomes level 3, return target creature card from your graveyard to the battlefield. You gain life equal to that creature's toughness.

Anguished Unmaking

Exile target nonland permanent. You lose 3 life.

Hero's Downfall

Celestial Mantle

Enchant creature
Enchanted creature gets +3/+3.
Whenever enchanted creature deals combat damage to a player, double its controller's life total.

Owlbear

Trample
Keen Senses — When this creature enters, draw a card.

Dina, Soul Steeper

Whenever you gain life, each opponent loses 1 life.
{1}, Sacrifice another creature: Dina gets +X/+0 until end of turn, where X is the sacrificed creature's power.

Soul's Attendant

Whenever another creature enters, you may gain 1 life.

Sam, Loyal Attendant

Partner with Frodo, Adventurous Hobbit (When this creature enters, target player may put Frodo into their hand from their library, then shuffle.)
At the beginning of combat on your turn, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
Activated abilities of Foods you control cost {1} less to activate.

Defiant Bloodlord

Flying
Whenever you gain life, target opponent loses that much life.

Luminous Phantom

Flying
Whenever another creature you control leaves the battlefield, you gain 1 life.
If Luminous Phantom would be put into a graveyard from anywhere, exile it instead.

Lunarch Veteran

Whenever another creature you control enters, you gain 1 life.
Disturb {1}{W} (You may cast this card from your graveyard transformed for its disturb cost.)

Lunarch Veteran // Luminous Phantom

Sol Ring

Shire Shirriff

Vigilance
When this creature enters, you may sacrifice a token. When you do, exile target creature an opponent controls until this creature leaves the battlefield.

Meriadoc Brandybuck

Whenever one or more Halflings you control attack a player, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")

Aven Battle Priest

Flying (This creature can't be blocked except by creatures with flying or reach.)
When this creature enters, you gain 3 life.

Soul Link

Enchant creature
Whenever enchanted creature deals damage, you gain that much life.
Whenever enchanted creature is dealt damage, you gain that much life.

Vizkopa Guildmage

{1}{W}{B}: Target creature gains lifelink until end of turn.
{1}{W}{B}: Whenever you gain life this turn, each opponent loses that much life.

Soul Warden

Whenever another creature enters, you gain 1 life.

Forest

Tavern Swindler

{T}, Pay 3 life: Flip a coin. If you win the flip, you gain 6 life.

Noble Purpose

Whenever a creature you control deals combat damage, you gain that much life.

Jewel Thief

Vigilance, trample
When this creature enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Treebeard, Gracious Host

Trample, ward {2}
When Treebeard enters, create two Food tokens.
Whenever you gain life, put that many +1/+1 counters on target Halfling or Treefolk.

Farmer Cotton

When this creature enters, create X 1/1 white Halfling creature tokens and X Food tokens. (They're artifacts with "{2}, {T}, Sacrifice this token: You gain 3 life.")