Rites of Initiation

Discard any number of cards at random. Creatures you control get +1/+0 until end of turn for each card discarded this way.

Blood Moon

Fervor

Creatures you control have haste. (They can attack and {T} as soon as they come under your control.)

Neheb, Dreadhorde Champion

Trample
Whenever Neheb, Dreadhorde Champion deals combat damage to a player or planeswalker, you may discard any number of cards. If you do, draw that many cards and add that much {R}. Until end of turn, you don't lose this mana as steps and phases end.

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.)

Vectis Gloves

Equipped creature gets +2/+0 and has artifact landwalk. (It can't be blocked as long as defending player controls an artifact land.)
Equip {2}

Ashiok, Wicked Manipulator

If you would pay life while your library has at least that many cards in it, exile that many cards from the top of your library instead.
+1: Look at the top two cards of your library. Exile one of them and put the other into your hand.
−2: Create two 1/1 black Nightmare creature tokens with "At the beginning of combat on your turn, if a card was put into exile this turn, put a +1/+1 counter on this creature."
−7: Target player exiles the top X cards of their library, where X is the total mana value of cards you own in exile.

Dangerous Wager

Malfegor

Flying
When Malfegor enters, discard your hand. Each opponent sacrifices a creature for each card discarded this way.

Cemetery Tampering

Hideaway 5 (When this enchantment enters, look at the top five cards of your library, exile one face down, then put the rest on the bottom in a random order.)
At the beginning of your upkeep, you may mill three cards. Then if there are twenty or more cards in your graveyard, you may play the exiled card without paying its mana cost.

Phyrexian Plaguelord

{T}, Sacrifice Phyrexian Plaguelord: Target creature gets -4/-4 until end of turn.
Sacrifice a creature: Target creature gets -1/-1 until end of turn.

Transmogrant Altar

{B}, {T}, Sacrifice a creature: Add {C}{C}{C}.
{2}, {T}, Sacrifice a creature: Create a 3/3 colorless Zombie artifact creature token. Activate only as a sorcery.

Mountain

Viscera Seer

Sacrifice a creature: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Bladewing, Deathless Tyrant

Flying, haste
Whenever Bladewing, Deathless Tyrant deals combat damage to a player or planeswalker, for each creature card in your graveyard, create a 2/2 black Zombie Knight creature token with menace.

Prowler's Helm

Equipped creature can't be blocked except by Walls.
Equip {2}

Goblin Bombardment

Sacrifice a creature: Goblin Bombardment deals 1 damage to any target.

Dark Triumph

If you control a Swamp, you may sacrifice a creature rather than pay this spell's mana cost.
Creatures you control get +2/+0 until end of turn.

Castle Embereth

Castle Embereth enters tapped unless you control a Mountain.
{T}: Add {R}.
{1}{R}{R}, {T}: Creatures you control get +1/+0 until end of turn.