Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for 1.) Flying At the beginning of your end step, each opponent discards a card. 1B, Sacrifice an artifact: Target creature gets -2/-2 until end of turn.
Ghastlord of Fugue is unblockable. Whenever Ghastlord of Fugue deals combat damage to a player, that player reveals his or her hand. Choose a card from it. That player removes that card from the game.
Double strike Eternalize 3WW (3WW, Exile this card from your graveyard: Create a token that's a copy of it, except it's a 4/4 black Zombie Cat with no mana cost. Eternalize only as a sorcery.)
Whenever a creature you control enters, it explores. (Reveal the top card of your library. Put that card into your hand if it’s a land. Otherwise, put a +1/+1 counter on the creature, then put the card back or put it into your graveyard.)
Draw a card for each creature you control. Ferocious — You gain 4 life for each creature you control with power 4 or greater.
When Necromancer’s Covenant enters, exile all creature cards from target player’s graveyard, then create a 2/2 black Zombie creature token for each card exiled this way. Zombies you control have lifelink.
Equipped creature has "2, T This creature deals 1 damage to target creature or player" and "Whenever a creature is put into a graveyard from play, untap this creature." Whenever a Shaman creature comes into play, you may attach Thornbite Staff to it. Equip 4
Other Goblin creatures you control attack each combat if able. At the beginning of combat on your turn, create a 1/1 red Goblin creature token with haste. Whenever Goblin Rabblemaster attacks, it gets +1/+0 until end of turn for each other attacking Goblin.
Flying Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.) At the beginning of combat on your turn, choose up to one target creature you control. Until end of turn, that creature gets +2/+0, gains trample if it’s red, and gains vigilance if it’s white. 2/5
Choose two — • Your opponents can’t gain life this turn. • Atarka’s Command deals 3 damage to each opponent. • You may put a land card from your hand onto the battlefield. • Creatures you control get +1/+1 and gain reach until end of turn.
Counter target spell unless its controller discards their hand. Transmute {1}{U}{B} ({1}{U}{B}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)
Etrata, the Silencer can’t be blocked. Whenever Etrata deals combat damage to a player, exile target creature that player controls and put a hit counter on that card. That player loses the game if they own three or more exiled cards with hit counters on them. Etrata’s owner shuffles Etrata into their library. 3/5
Colorless spells you cast cost {2} less to cast. +1: Exile the top card of your library face down and look at it. Create a 2/2 colorless Spirit creature token. When that token leaves the battlefield, put the exiled card into your hand. −3: Destroy target permanent that’s one or more colors. Loyalty: 4
Hideaway 4 (When this land enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.) Windbrisk Heights enters tapped. {T}: Add {W}. {W}, {T}: You may play the exiled card without paying its mana cost if you attacked with three or more creatures this turn.