Moment's Peace

Prevent all combat damage that would be dealt this turn.
Flashback {2}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

City of Brass

Whenever this land becomes tapped, it deals 1 damage to you.
{T}: Add one mana of any color.

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.

Ethereal Haze

Prevent all damage that would be dealt by creatures this turn.

Timeless Lotus

Timeless Lotus enters tapped.
{T}: Add {W}{U}{B}{R}{G}.

Gemstone Mine

This land enters with three mining counters on it.
{T}, Remove a mining counter from this land: Add one mana of any color. If there are no mining counters on this land, sacrifice it.

The Countdown Is at One

Players play a Magic subgame, starting at 1 life and using their libraries as their decks. For the rest of the main game, if a source would deal damage to a player who didn't win the subgame, it deals double that damage to that player instead.

Spore Frog

Sacrifice this creature: Prevent all combat damage that would be dealt this turn.

Callidus Assassin

Flash
Polymorphine — You may have this creature enter tapped as a copy of any creature on the battlefield, except it has "When this creature enters, destroy up to one other target creature with the same name as this creature."

Prevent all combat damage that would be dealt this turn.

Thraximundar

Haste
Whenever Thraximundar attacks, defending player sacrifices a creature of their choice.
Whenever a player sacrifices a creature, you may put a +1/+1 counter on Thraximundar.

Enter the Dungeon

Players play a Magic subgame under the table, starting at 5 life and using their libraries as their decks. The winner searches their library for two cards, puts those cards into their hand, then shuffles.

Double Deal

Choose another player. Double Deal deals 3 damage to that player. At the beginning of the first upkeep in your next game with that player, Double Deal deals 3 damage to the player.

Stocking Tiger

Stocking Tiger enters with a sealed Magic booster pack under it.
When Stocking Tiger deals combat damage to a player, unwrap the booster pack and put it into your hand.

Lotus Bloom

Suspend 3—{0} (Rather than cast this card from your hand, pay {0} and exile it with three time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)
{T}, Sacrifice this artifact: Add three mana of any one color.

Karn Liberated

+4: Target player exiles a card from their hand.
−3: Exile target permanent.
−14: Restart the game, leaving in exile all non-Aura permanent cards exiled with Karn. Then put those cards onto the battlefield under your control.

Lotus Field

Hexproof
This land enters tapped.
When this land enters, sacrifice two lands.
{T}: Add three mana of any one color.

Gemstone Caverns

If this card is in your opening hand and you're not the starting player, you may begin the game with Gemstone Caverns on the battlefield with a luck counter on it. If you do, exile a card from your hand.
{T}: Add {C}. If Gemstone Caverns has a luck counter on it, instead add one mana of any color.

Quietus Spike

Equipped creature has deathtouch.
Whenever equipped creature deals combat damage to a player, that player loses half their life, rounded up.
Equip {3}

Ezio Auditore da Firenze

Menace
Assassin spells you cast have freerunning {B}{B}. (You may cast a spell for its freerunning cost if you dealt combat damage to a player this turn with an Assassin or commander.)
Whenever Ezio deals combat damage to a player, you may pay {W}{U}{B}{R}{G} if that player has 10 or less life. When you do, that player loses the game.

Mana Confluence

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

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Kami of False Hope

Access Tunnel

{T}: Add {C}.
{3}, {T}: Target creature with power 3 or less can't be blocked this turn.

Shahrazad

Players play a Magic subgame, using their libraries as their decks. Each player who doesn't win the subgame loses half their life, rounded up.

Time Machine

{T}: Exile this artifact and target nontoken creature you own. Return them to the battlefield at the beginning of your upkeep on your turn X in the next game you play with one of your opponents in this game, where X is the mana value of the exiled creature.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Forbidden Orchard

{T}: Add one mana of any color.
Whenever you tap this land for mana, target opponent creates a 1/1 colorless Spirit creature token.

Zirda, the Dawnwaker

Companion — Each permanent card in your starting deck has an activated ability. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
Abilities you activate that aren't mana abilities cost {2} less to activate. This effect can't reduce the mana in that cost to less than one mana.
{1}, {T}: Target creature can't block this turn.