Crystal Rod

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

Demon's Horn

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

Dragon's Claw

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

Rod of Absorption

Whenever a player casts an instant or sorcery spell, exile it instead of putting it into a graveyard as it resolves.
{X}, {T}, Sacrifice Rod of Absorption: You may cast any number of spells from among cards exiled with Rod of Absorption with total mana value X or less without paying their mana costs.

River Song's Diary

Imprint — Whenever a player casts an instant or sorcery spell from their hand, exile it instead of putting it into a graveyard as it resolves.
At the beginning of your upkeep, if there are four or more cards exiled with River Song's Diary, choose one of them at random. You may cast it without paying its mana cost.

Wooden Sphere

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

Ivory Cup

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

Soul's Attendant

Whenever another creature enters, you may gain 1 life.

Authority of the Consuls

Creatures your opponents control enter tapped.
Whenever a creature an opponent controls enters, you gain 1 life.

Auriok Champion

Protection from black and from red
Whenever another creature enters, you may gain 1 life.

Ancient Den

Soul Warden

Whenever another creature enters, you gain 1 life.

Apothecary Initiate

Zenith Chronicler

Whenever a player casts their first multicolored spell each turn, each other player draws a card.

Kraken's Eye

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

Throne of Bone

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

Jeweled Torque

As Jeweled Torque enters, choose a color.
Whenever a player casts a spell of the chosen color, you may pay {2}. If you do, you gain 2 life.

Confessor

Whenever a player discards a card, you may gain 1 life.

Titania's Chosen

Whenever a player casts a green spell, put a +1/+1 counter on Titania's Chosen.

Forgotten Ancient

Whenever a player casts a spell, you may put a +1/+1 counter on Forgotten Ancient.
At the beginning of your upkeep, you may move any number of +1/+1 counters from Forgotten Ancient onto other creatures.

Powerleech

Whenever an artifact an opponent controls becomes tapped or an opponent activates an artifact's ability without {T} in its activation cost, you gain 1 life.

Managorger Hydra

Trample
Whenever a player casts a spell, put a +1/+1 counter on Managorger Hydra.

Urborg, Tomb of Yawgmoth

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

Angel's Feather

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

Lifetap

Whenever a Forest an opponent controls becomes tapped, you gain 1 life.

Polluted Bonds

Whenever a land an opponent controls enters, that player loses 2 life and you gain 2 life.

Ageless Entity

Whenever you gain life, put that many +1/+1 counters on Ageless Entity.

Ajani's Pridemate

Whenever you gain life, put a +1/+1 counter on this creature.

Golem's Heart

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

Painter's Servant

As Painter's Servant enters, choose a color.
All cards that aren't on the battlefield, spells, and permanents are the chosen color in addition to their other colors.

Roots of Life

As Roots of Life enters, choose Island or Swamp.
Whenever a land of the chosen type an opponent controls becomes tapped, you gain 1 life.

Yavimaya, Cradle of Growth

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

Kor Firewalker

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

Paradise Plume

As Paradise Plume enters, choose a color.
Whenever a player casts a spell of the chosen color, you may gain 1 life.
{T}: Add one mana of the chosen color.

Spectrum Sentinel

Protection from multicolored (This creature can't be blocked, targeted, dealt damage, enchanted, or equipped by anything multicolored.)
Whenever a nonbasic land an opponent controls enters, you gain 1 life.

Lifeblood

Whenever a Mountain an opponent controls becomes tapped, you gain 1 life.

Urza's Chalice

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

Nurturer Initiate

Whenever a player casts a green spell, you may pay {1}. If you do, target creature gets +1/+1 until end of turn.

Wurm's Tooth

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

Iron Star

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

Geometric Nexus

Whenever a player casts an instant or sorcery spell, put a number of charge counters on Geometric Nexus equal to that spell's mana value.
{6}, {T}, Remove all charge counters from Geometric Nexus: Create a 0/0 green and blue Fractal creature token. Put X +1/+1 counters on it, where X is the number of charge counters removed this way.