Seething Song

Exploration

You may play an additional land on each of your turns.

Impromptu Raid

{2}{R/G}: Reveal the top card of your library. If it isn't a creature card, put it into your graveyard. Otherwise, put that card onto the battlefield. That creature gains haste. Sacrifice it at the beginning of the next end step.

Simian Spirit Guide

Exile Simian Spirit Guide from your hand: Add {R}.

Worldspine Wurm

Trample
When Worldspine Wurm dies, create three 5/5 green Wurm creature tokens with trample.
When Worldspine Wurm is put into a graveyard from anywhere, shuffle it into its owner's library.

Through the Breach

You may put a creature card from your hand onto the battlefield. That creature gains haste. Sacrifice that creature at the beginning of the next end step.
Splice onto Arcane {2}{R}{R} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Sneak Attack

{R}: You may put a creature card from your hand onto the battlefield. That creature gains haste. Sacrifice the creature at the beginning of the next end step.

Mountain

Gamble

Search your library for a card, put that card into your hand, discard a card at random, then shuffle.

Pathrazer of Ulamog

Annihilator 3 (Whenever this creature attacks, defending player sacrifices three permanents of their choice.)
Pathrazer of Ulamog can't be blocked except by three or more creatures.

Courser of Kruphix

Play with the top card of your library revealed.
You may play lands from the top of your library.
Landfall — Whenever a land you control enters, you gain 1 life.

Emrakul, the Promised End

This spell costs {1} less to cast for each card type among cards in your graveyard.
When you cast this spell, you gain control of target opponent during that player's next turn. After that turn, that player takes an extra turn.
Flying, trample, protection from instants

Mana Flare

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