Deadly Rollick

If you control a commander, you may cast this spell without paying its mana cost.
Exile target creature.

Three Visits

Search your library for a Forest card, put it onto the battlefield, then shuffle.

Mana Confluence

{T}, Pay 1 life: Add one mana of any color.

Blood Crypt

({T}: Add {B} or {R}.)
As Blood Crypt enters, you may pay 2 life. If you don't, it enters tapped.

Mana Drain

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

Darksteel Citadel

Chrome Mox

Imprint — When Chrome Mox enters, you may exile a nonartifact, nonland card from your hand.
{T}: Add one mana of any of the exiled card's colors.

Mana Crypt

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}.

Teferi's Protection

Until your next turn, your life total can't change and you gain protection from everything. All permanents you control phase out. (While they're phased out, they're treated as though they don't exist. They phase in before you untap during your untap step.)
Exile Teferi's Protection.

Bojuka Bog

Bojuka Bog enters tapped.
When Bojuka Bog enters, exile target player's graveyard.
{T}: Add {B}.

Lotus Cobra

Landfall — Whenever a land you control enters, add one mana of any color.

Summoner's Pact

Search your library for a green creature card, reveal it, put it into your hand, then shuffle.
At the beginning of your next upkeep, pay {2}{G}{G}. If you don't, you lose the game.

Underworld Breach

Each nonland card in your graveyard has escape. The escape cost is equal to the card's mana cost plus exile three other cards from your graveyard. (You may cast cards from your graveyard for their escape cost.)
At the beginning of the end step, sacrifice Underworld Breach.

Eternal Witness

When Eternal Witness enters, you may return target card from your graveyard to your hand.

Mox Opal

Metalcraft — {T}: Add one mana of any color. Activate only if you control three or more artifacts.

Birds of Paradise

Deflecting Swat

If you control a commander, you may cast this spell without paying its mana cost.
You may choose new targets for target spell or ability.

Ad Nauseam

Reveal the top card of your library and put that card into your hand. You lose life equal to its mana value. You may repeat this process any number of times.

Illusionist's Bracers

Whenever an ability of equipped creature is activated, if it isn't a mana ability, copy that ability. You may choose new targets for the copy.
Equip {3}

Demonic Tutor

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

Entomb

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

Wood Elves

When Wood Elves enters, search your library for a Forest card, put that card onto the battlefield, then shuffle.

Slaughter Pact

Destroy target nonblack creature.
At the beginning of your next upkeep, pay {2}{B}. If you don't, you lose the game.

Kenrith, the Returned King

{R}: All creatures gain trample and haste until end of turn.
{1}{G}: Put a +1/+1 counter on target creature.
{2}{W}: Target player gains 5 life.
{3}{U}: Target player draws a card.
{4}{B}: Put target creature card from a graveyard onto the battlefield under its owner's control.

Aether Hub

When Aether Hub enters, you get {E} (an energy counter).
{T}: Add {C}.
{T}, Pay {E}: Add one mana of any color.