Zhur-Taa Ancient

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

Overabundance

Whenever a player taps a land for mana, that player adds one mana of any type that land produced, and this enchantment deals 1 damage to the player.

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.

Urborg, Tomb of Yawgmoth

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

Tunneling Geopede

Landfall — Whenever a land you control enters, this creature deals 1 damage to each opponent.

Zo-Zu the Punisher

Whenever a land enters, Zo-Zu deals 2 damage to that land's controller.

Tunnel Ignus

Whenever a land enters under an opponent's control, if that player had another land enter the battlefield under their control this turn, this creature deals 3 damage to that player.

Spitfire Lagac

Rootweaver Druid

When this creature enters, each opponent may search their library for up to three basic land cards. They each put one of those cards onto the battlefield tapped under your control and the rest onto the battlefield tapped under their control. Then each player who searched their library this way shuffles.

Eladamri's Vineyard

At the beginning of each player's first main phase, that player adds {G}{G}.

Magus of the Vineyard

Blanket of Night

Heartbeat of Spring

Horizon Stone

If you would lose unspent mana, that mana becomes colorless instead.

Mana Reflection

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

Yurlok of Scorch Thrash

Vigilance
A player losing unspent mana causes that player to lose that much life.
{1}, {T}: Each player adds {B}{R}{G}.

Belbe, Corrupted Observer

At the beginning of each postcombat main phase, the active player adds {C}{C} for each of your opponents who lost life this turn. (Damage causes loss of life.)

Omnath, Locus of Mana

You don't lose unspent green mana as steps and phases end.
Omnath gets +1/+1 for each unspent green mana you have.

Extraplanar Lens

Imprint — When this artifact enters, you may exile target land you control.
Whenever a land with the same name as the exiled card is tapped for mana, its controller adds one mana of any type that land produced.

Gauntlet of Power

As this artifact enters, choose a color.
Creatures of the chosen color get +1/+1.
Whenever a basic land is tapped for mana of the chosen color, its controller adds an additional one mana of that color.

Mana Flare

Invader Parasite

Imprint — When this creature enters, exile target land.
Whenever a land an opponent controls with the same name as the exiled card enters, this creature deals 2 damage to that player.

Price of Glory

Whenever a player taps a land for mana, if it's not that player's turn, destroy that land.

Ankh of Mishra

Whenever a land enters, this artifact deals 2 damage to that land's controller.

Yavimaya, Cradle of Growth

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

Shizuko, Caller of Autumn

At the beginning of each player's upkeep, that player adds {G}{G}{G}. Until end of turn, they don't lose this mana as steps and phases end.