Whenever you cast a spell, you gain 1 life for each spell you've cast this turn.

Pay 50 life: Aetherflux Reservoir deals 50 damage to any target.

{T}: Add {C}{C}. Ancient Tomb deals 2 damage to you.

Enchant creature card in a graveyard

When Animate Dead enters the battlefield, if it's on the battlefield, it loses "enchant creature card in a graveyard" and gains "enchant creature put onto the battlefield with Animate Dead." Return enchanted creature card to the battlefield under your control and attach Animate Dead to it. When Animate Dead leaves the battlefield, that creature's controller sacrifices it.

Enchanted creature gets -1/-0.

{T}: Add one mana of any color in your commander's color identity.

Whenever Ayara, First of Locthwain or another black creature enters the battlefield under your control, each opponent loses 1 life and you gain 1 life.

{T}, Sacrifice another black creature: Draw a card.

Bojuka Bog enters the battlefield tapped.

When Bojuka Bog enters the battlefield, exile target player's graveyard.

{T}: Add {B}.

You may look at the top card of your library any time.

You may play lands and cast spells from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.

{T}, Sacrifice ten nonland permanents: Each opponent loses 10 life.

Until end of turn, whenever a player taps a Swamp for mana, that player adds an additional {B}.

{2}, {T}: Add {B} for each Swamp you control.

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)

Whenever you tap a Swamp for mana, add an additional {B}.

As an additional cost to cast this spell, sacrifice a creature.

Add {B}{B}{B}{B}.

Add {B}{B}{B}.

Shadow (This creature can block or be blocked by only creatures with shadow.)

If a card would be put into an opponent's graveyard from anywhere, instead exile it with a void counter on it.

{T}, Sacrifice Dauthi Voidwalker: Choose an exiled card an opponent owns with a void counter on it. You may play it this turn without paying its mana cost.

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

Flash

Whenever a creature you control dies, each opponent sacrifices a creature.

{2}, {T}, Sacrifice Expedition Map: Search your library for a land card, reveal it, put it into your hand, then shuffle.

Each opponent loses X life. You gain life equal to the life lost this way.

Whenever a creature you control dies, each other player sacrifices a creature.

Black spells you cast cost {1} less to cast.

{T}, Sacrifice Jeweled Lotus: Add three mana of any one color. Spend this mana only to cast your commander.

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)

Equip {0}

{T}, Sacrifice Lotus Petal: Add one mana of any color.

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you.

{T}: Add {C}{C}.

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)

Whenever a Human deals damage to you, destroy it.

Other non-Human creatures you control get +1/+1 and have undying. (When a creature with undying dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

{T}: Add {C}.

{1}, {T}, Sacrifice Mind Stone: Draw a card.

You draw two cards and you lose 2 life.

{T}: Add {C}.

{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to its mana value.

You have no maximum hand size.

{T}: Add {C}.

{1}: Look at the top three cards of your library, then put them back in any order.

{T}: Draw a card, then put Sensei's Divining Top on top of its owner's library.

Target player draws two cards and loses 2 life.

Equipped creature gets +1/-1.

Whenever equipped creature dies, draw two cards.

Equip {1}

{T}: Add {C}{C}.

Whenever one or more cards leave your graveyard, create a tapped 2/2 black Zombie creature token.

Partner (You can have two commanders if both have partner.)

As an additional cost to cast this spell, pay X life.

All creatures get -X/-X until end of turn.

Triskelion enters the battlefield with three +1/+1 counters on it.

Remove a +1/+1 counter from Triskelion: It deals 1 damage to any target.

Each land is a Swamp in addition to its other land types.

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Walking Ballista enters the battlefield with X +1/+1 counters on it.

{4}: Put a +1/+1 counter on Walking Ballista.

Remove a +1/+1 counter from Walking Ballista: It deals 1 damage to any target.