Llanowar Elves

Sakiko, Mother of Summer

Whenever a creature you control deals combat damage to a player, add that much {G}. Until end of turn, you don't lose this mana as steps and phases end.

Deathbloom Gardener

Deathtouch
{T}: Add one mana of any color.

Doubling Cube

{3}, {T}: Double the amount of each type of unspent mana you have.

Elvish Mystic

Vernal Bloom

Whenever a Forest is tapped for mana, its controller adds an additional {G}.

Keeper of Progenitus

Whenever a player taps a Mountain, Forest, or Plains for mana, that player adds one mana of any type that land produced.

Dictate of Karametra

Flash
Whenever a player taps a land for mana, that player adds one mana of any type that land produced.

Hall of Gemstone

At the beginning of each player's upkeep, that player chooses a color. Until end of turn, lands tapped for mana produce mana of the chosen color instead of any other color.

Ant Queen

{1}{G}: Create a 1/1 green Insect creature token.

Early Harvest

Target player untaps all basic lands they control.

Heartbeat of Spring

Whenever a player taps a land for mana, that player adds one mana of any type that land produced.

Priest of Titania

{T}: Add {G} for each Elf on the battlefield.

Llanowar Tribe

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Nyxbloom Ancient

Trample
If you tap a permanent for mana, it produces three times as much of that mana instead.

Zendikar Resurgent

Whenever you tap a land for mana, add one mana of any type that land produced. (The types of mana are white, blue, black, red, green, and colorless.)
Whenever you cast a creature spell, draw a card.

Summer Bloom

You may play up to three additional lands this turn.

Mana Reflection

If you tap a permanent for mana, it produces twice as much of that mana instead.

Leyline of Abundance

If Leyline of Abundance is in your opening hand, you may begin the game with it on the battlefield.
Whenever you tap a creature for mana, add an additional {G}.
{6}{G}{G}: Put a +1/+1 counter on each creature you control.