Downhill Charge

You may sacrifice a Mountain rather than pay this spell's mana cost.
Target creature gets +X/+0 until end of turn, where X is the number of Mountains you control.

Library of Leng

You have no maximum hand size.
If an effect causes you to discard a card, discard it, but you may put it on top of your library instead of into your graveyard.

Tahngarth's Rage

Enchant creature
Enchanted creature gets +3/+0 as long as it's attacking. Otherwise, it gets -2/-1.

Hand of Vecna

At the beginning of combat on your turn, equipped creature or a creature you control named Vecna gets +X/+X until end of turn, where X is the number of cards in your hand.
Equip—Pay 1 life for each card in your hand.
Equip {2}

Taurean Mauler

Changeling (This card is every creature type.)
Whenever an opponent casts a spell, you may put a +1/+1 counter on this creature.

Goblin War Paint

Enchant creature
Enchanted creature gets +2/+2 and has haste.

Amok

{1}, Discard a card at random: Put a +1/+1 counter on target creature.

Junk Jet

When this Equipment enters, create a Junk token. (It's an artifact with "{T}, Sacrifice this token: Exile the top card of your library. You may play that card this turn. Activate only as a sorcery.")
{3}, Sacrifice another artifact: Double equipped creature's power until end of turn.
Equip {1}

Ogre's Cleaver

Fiery Mantle

Enchant creature
{R}: Enchanted creature gets +1/+0 until end of turn.
When this Aura is put into a graveyard from the battlefield, return it to its owner's hand.

Coral Helm

{3}, Discard a card at random: Target creature gets +2/+2 until end of turn.

Trusty Machete

Empyrial Plate

Equipped creature gets +1/+1 for each card in your hand.
Equip {2}

Lunar Frenzy

Target creature you control gets +X/+0 and gains first strike and trample until end of turn.

Magefire Wings

Enchant creature
Enchanted creature gets +2/+0 and has flying.

War-Trained Slasher

Menace (This creature can't be blocked except by two or more creatures.)
Whenever this creature attacks a battle, double its power until end of turn.

Startling Development

Until end of turn, target creature becomes a blue Serpent with base power and toughness 4/4.
Cycling {1} ({1}, Discard this card: Draw a card.)

Escape Velocity

Enchant creature
Enchanted creature gets +1/+0 and has haste.
Escape—{1}{R}, Exile two other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Ghitu War Cry

{R}: Target creature gets +1/+0 until end of turn.

Captain Howler, Sea Scourge

Ward—{2}, Pay 2 life.
Whenever you discard one or more cards, target creature gets +2/+0 until end of turn for each card discarded this way. Whenever that creature deals combat damage to a player this turn, you draw a card.

Giant Strength

Enchant creature
Enchanted creature gets +2/+2.

Pedal to the Metal

Target creature gets +X/+0 and gains first strike until end of turn.

Greataxe

Equipped creature gets +4/+0.
Equip {5} ({5}: Attach to target creature you control. Equip only as a sorcery.)

Captive Flame

Blood Lust

If target creature has toughness 5 or greater, it gets +4/-4 until end of turn. Otherwise, it gets +4/-X until end of turn, where X is its toughness minus 1.

Ironhoof Boar

Trample, haste
Channel — {1}{R}, Discard this card: Target creature gets +3/+1 and gains trample until end of turn.

Power Matrix

{T}: Target creature gets +1/+1 and gains flying, first strike, and trample until end of turn.

Bloodforged Battle-Axe

Equipped creature gets +2/+0.
Whenever equipped creature deals combat damage to a player, create a token that's a copy of this Equipment.
Equip {2}

Enthusiastic Study

Target creature gets +3/+1 and gains trample until end of turn.
Learn. (You may reveal a Lesson card you own from outside the game and put it into your hand, or discard a card to draw a card.)

One With the Wind

Enchant creature
Enchanted creature gets +2/+2 and has flying.

Chainsaw

When this Equipment enters, it deals 3 damage to up to one target creature.
Whenever one or more creatures die, put a rev counter on this Equipment.
Equipped creature gets +X/+0, where X is the number of rev counters on this Equipment.
Equip {3}

Magmatic Channeler

As long as there are four or more instant and/or sorcery cards in your graveyard, this creature gets +3/+1.
{T}, Discard a card: Exile the top two cards of your library, then choose one of them. You may play that card this turn.

Robe of the Archmagi

Whenever equipped creature deals combat damage to a player, you draw that many cards.
Equip {4}
Equip Shaman, Warlock, or Wizard {1}

You Come to a River

Choose one —
• Fight the Current — Return target nonland permanent to its owner's hand.
• Find a Crossing — Target creature gets +1/+0 until end of turn and can't be blocked this turn.

Eel Umbra

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature gets +1/+1.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Livaan, Cultist of Tiamat

Whenever you cast a noncreature spell, target creature gets +X/+0 until end of turn, where X is that spell's mana value.
Choose a Background (You can have a Background as a second commander.)