Ransack the Lab

Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.

Insolent Neonate

Menace (This creature can't be blocked except by two or more creatures.)
Discard a card, Sacrifice Insolent Neonate: Draw a card.

Breaker of Creation

When you cast this spell, you gain 1 life for each colorless permanent you control.
Hexproof from each color
Annihilator 2 (Whenever this creature attacks, defending player sacrifices two permanents of their choice.)

Death

Return target creature card from your graveyard to the battlefield. You lose life equal to its mana value.

Life

All lands you control become 1/1 creatures until end of turn. They're still lands.

Life // Death

Dark Ritual

Buried Alive

Search your library for up to three creature cards, put them into your graveyard, then shuffle.

Smoldering Marsh

({T}: Add {B} or {R}.)
Smoldering Marsh enters tapped unless you control two or more basic lands.

Inquisition of Kozilek

Target player reveals their hand. You choose a nonland card from it with mana value 3 or less. That player discards that card.

Cathartic Reunion

As an additional cost to cast this spell, discard two cards.
Draw three cards.

Dragonskull Summit

Dragonskull Summit enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Mountain

Lightning Axe

As an additional cost to cast this spell, discard a card or pay {5}.
Lightning Axe deals 5 damage to target creature.

Swamp

Persist

Return target nonlegendary creature card from your graveyard to the battlefield with a -1/-1 counter on it.

Gemstone Mine

Gemstone Mine enters with three mining counters on it.
{T}, Remove a mining counter from Gemstone Mine: Add one mana of any color. If there are no mining counters on Gemstone Mine, sacrifice it.

Troll of Khazad-dûm

Troll of Khazad-dûm can't be blocked except by three or more creatures.
Swampcycling {1} ({1}, Discard this card: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.)

Hellkite Overlord

Flying, trample, haste
{R}: Hellkite Overlord gets +1/+0 until end of turn.
{B}{G}: Regenerate Hellkite Overlord.

Oliphaunt

Trample
Whenever Oliphaunt attacks, another target creature you control gets +2/+0 and gains trample until end of turn.
Mountaincycling {1} ({1}, Discard this card: Search your library for a Mountain card, reveal it, put it into your hand, then shuffle.)

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)