Propaganda

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Psychic Drain

Target player mills X cards and you gain X life.

Sword Coast Sailor

Commander creatures you own have "Whenever this creature attacks a player, if no opponent has more life than that player, this creature can't be blocked this turn."

Louisoix's Sacrifice

As an additional cost to cast this spell, sacrifice a legendary creature or pay {2}.
Counter target activated ability, triggered ability, or noncreature spell.

Swallowed by Leviathan

Choose target spell. Surveil 2, then counter the chosen spell unless its controller pays {1} for each card in your graveyard. (To surveil 2, look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Nemesis of Reason

Whenever this creature attacks, defending player mills ten cards.

Reflections of Littjara

As this enchantment enters, choose a creature type.
Whenever you cast a spell of the chosen type, copy that spell. (A copy of a permanent spell becomes a token.)

Absorb

Herald's Horn

As this artifact enters, choose a creature type.
Creature spells you cast of the chosen type cost {1} less to cast.
At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

Metallic Mimic

As this creature enters, choose a creature type.
This creature is the chosen type in addition to its other types.
Each other creature you control of the chosen type enters with an additional +1/+1 counter on it.

Arm the Cathars

Until end of turn, target creature gets +3/+3, up to one other target creature gets +2/+2, and up to one other target creature gets +1/+1. Those creatures gain vigilance until end of turn.

Hidden Strings

You may tap or untap target permanent, then you may tap or untap another target permanent.
Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

Spiral into Solitude

Enchant creature
Enchanted creature can't attack or block.
{1}{W}, Blight 1, Sacrifice this Aura: Exile enchanted creature. (To blight 1, put a -1/-1 counter on a creature you control.)

The Water Crystal

Blue spells you cast cost {1} less to cast.
If an opponent would mill one or more cards, they mill that many cards plus four instead.
{4}{U}{U}, {T}: Each opponent mills cards equal to the number of cards in your hand.

Nihiloor

When Nihiloor enters, for each opponent, tap up to one untapped creature you control. When you do, gain control of target creature that player controls with power less than or equal to the tapped creature's power for as long as you control Nihiloor.
Whenever you attack with a creature an opponent owns, you gain 2 life and that player loses 2 life.

Crossroads Village

This land enters tapped. As it enters, choose a color.
{T}: Add one mana of the chosen color.

Dinrova Horror

When this creature enters, return target permanent to its owner's hand, then that player discards a card.

Captain N'ghathrod

Horrors you control have menace.
Whenever a Horror you control deals combat damage to a player, that player mills that many cards.
At the beginning of your end step, choose target artifact or creature card in an opponent's graveyard that was put there from their library this turn. Put it onto the battlefield under your control.

Vio, the Last Word

Whenever you counter a spell or ability, gain an experience counter.

At the beginning of your end step, you may create Spawn of Krothuss, a legendary 0/0 blue Kraken horror creature token with "This token gets +1/+1 for each experience counter you have."

Insomnia, Crown City

This land enters tapped.
{T}: Add {W} or {B}.

Keep Out

Choose one —
• Keep Out deals 4 damage to target tapped creature.
• Destroy target enchantment.

Command Tower

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

Gluttonous Slug

Menace
Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

Thrummingbird

Flying
Whenever this creature deals combat damage to a player, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Twist Reality

Choose one —
• Counter target spell.
• Manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Hullbreaker Horror

Flash
This spell can't be countered.
Whenever you cast a spell, choose up to one —
• Return target spell you don't control to its owner's hand.
• Return target nonland permanent to its owner's hand.

Perfect Intimidation

Choose one or both —
• Target opponent exiles two cards from their hand.
• Remove all counters from target creature.

Sol Ring

Triskaidekaphobia

At the beginning of your upkeep, choose one —
• Each player with exactly 13 life loses the game, then each player gains 1 life.
• Each player with exactly 13 life loses the game, then each player loses 1 life.

Irenicus's Vile Duplication

Create a token that's a copy of target creature you control, except the token has flying and it isn't legendary.

Annul

Counter target artifact or enchantment spell.

Convolute

Counter target spell unless its controller pays {4}.

Mindstatic

Counter target spell unless its controller pays {6}.

Piercing Light

Piercing Light deals 2 damage to target attacking or blocking creature. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)