Wrenn and Realmbreaker

Lands you control have "{T}: Add one mana of any color."
+1: Up to one target land you control becomes a 3/3 Elemental creature with vigilance, hexproof, and haste until your next turn. It's still a land.
−2: Mill three cards. You may put a permanent card from among the milled cards into your hand.
−7: You get an emblem with "You may play lands and cast permanent spells from your graveyard."

Stirring Wildwood

Stirring Wildwood enters tapped.
{T}: Add {G} or {W}.
{1}{G}{W}: Until end of turn, Stirring Wildwood becomes a 3/4 green and white Elemental creature with reach. It's still a land.

Plasma Elemental

Archway Commons

Archway Commons enters tapped.
When Archway Commons enters, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.

Spitemare

Whenever Spitemare is dealt damage, it deals that much damage to any target.

Market

Aftermath (Cast this spell only from your graveyard. Then exile it.)
Draw two cards, then discard two cards.

Farm

Destroy target attacking or blocking creature.

Farm // Market

Cascading Cataracts

Indestructible
{T}: Add {C}.
{5}, {T}: Add five mana in any combination of colors.

Chromanticore

Bestow {2}{W}{U}{B}{R}{G} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Flying, first strike, vigilance, trample, lifelink
Enchanted creature gets +4/+4 and has flying, first strike, vigilance, trample, and lifelink.

Forest

Prismatic Omen

Lands you control are every basic land type in addition to their other types.

Plains

Horde of Notions

Vigilance, trample, haste
{W}{U}{B}{R}{G}: You may play target Elemental card from your graveyard without paying its mana cost.

Fusion Elemental

Living Hive

Trample
Whenever Living Hive deals combat damage to a player, create that many 1/1 green Insect creature tokens.

Foundry Champion

When Foundry Champion enters, it deals damage to any target equal to the number of creatures you control.
{R}: Foundry Champion gets +1/+0 until end of turn.
{W}: Foundry Champion gets +0/+1 until end of turn.

Fertile Ground

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional one mana of any color.

Island

Collector's Vault

{2}, {T}: Draw a card, then discard a card. Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Deepfire Elemental

{X}{X}{1}: Destroy target artifact or creature with mana value X.

Morselhoarder

Morselhoarder enters with two -1/-1 counters on it.
Remove a -1/-1 counter from Morselhoarder: Add one mana of any color.

Flamekin Harbinger

When Flamekin Harbinger enters, you may search your library for an Elemental card, reveal it, then shuffle and put that card on top.