Gaea's Might

Domain — Target creature gets +1/+1 until end of turn for each basic land type among lands you control.

Blighted Agent

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Blighted Agent can't be blocked.

Gemstone Caverns

If Gemstone Caverns is in your opening hand and you're not the starting player, you may begin the game with Gemstone Caverns on the battlefield with a luck counter on it. If you do, exile a card from your hand.
{T}: Add {C}. If Gemstone Caverns has a luck counter on it, instead add one mana of any color.

Seachrome Coast

Seachrome Coast enters the battlefield tapped unless you control two or fewer other lands.
{T}: Add {W} or {U}.

Glistener Elf

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Boseiju, Who Endures

{T}: Add {G}.
Channel — {1}{G}, Discard Boseiju, Who Endures: Destroy target artifact, enchantment, or nonbasic land an opponent controls. That player may search their library for a land card with a basic land type, put it onto the battlefield, then shuffle. This ability costs {1} less to activate for each legendary creature you control.

Serum Powder

{T}: Add {C}.
Any time you could mulligan and Serum Powder is in your hand, you may exile all the cards from your hand, then draw that many cards. (You can do this in addition to taking mulligans.)

Leyline of the Guildpact

If Leyline of the Guildpact is in your opening hand, you may begin the game with it on the battlefield.
Each nonland permanent you control is all colors.
Lands you control are every basic land type in addition to their other types.

Nishoba Brawler

Trample
Domain — Nishoba Brawler's power is equal to the number of basic land types among lands you control.

Leyline Binding

Flash
Domain — This spell costs {1} less to cast for each basic land type among lands you control.
When Leyline Binding enters the battlefield, exile target nonland permanent an opponent controls until Leyline Binding leaves the battlefield.

Yavimaya, Cradle of Growth

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

Territorial Kavu

Domain — Territorial Kavu's power and toughness are each equal to the number of basic land types among lands you control.
Whenever Territorial Kavu attacks, choose one —
• Discard a card. If you do, draw a card.
• Exile up to one target card from a graveyard.

Blessing of the Nephilim

Enchant creature
Enchanted creature gets +1/+1 for each of its colors.

Might of Alara

Scion of Draco

Domain — This spell costs {2} less to cast for each basic land type among lands you control.
Flying
Each creature you control has vigilance if it's white, hexproof if it's blue, lifelink if it's black, first strike if it's red, and trample if it's green.

Inkmoth Nexus

{T}: Add {C}.
{1}: Inkmoth Nexus becomes a 1/1 Phyrexian Blinkmoth artifact creature with flying and infect until end of turn. It's still a land. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Boon of Boseiju

Target creature gets +X/+X until end of turn, where X is the greatest mana value among permanents you control. Untap it.