mtg.wtf

{T}: Target creature gets +1/+1 until end of turn.

As long as X is in X's owner's opponent's hand, X's owner may cast X and activate X's abilities. That opponent can't cast X and plays with their hand revealed.
{U}{B}, {T}: Put X into target opponent's hand.
{3}{U}{B}: You may play a land or cast a spell from the hand X is in. If you cast a spell this way, you cast it without paying its mana cost.

At the beginning of your upkeep, choose target opponent. Until end of turn, that player can't cast spells, you may look at the top card of their library any time, you may play the top card of their library, and you may spend mana as though it were mana of any color to cast spells this way.

Xander's Lounge enters tapped.
Cycling {3}

Casualty 2
Each opponent exiles the top card of their library. You may cast spells from among those cards this turn. If you cast a spell this way, pay life equal to that spell's mana value rather than pay its mana cost.

Whenever one or more creatures you control die, draft a card from Xander's Wake's spellbook. This ability triggers only once each turn.

Sacrifice a permanent: Regenerate target creature.

Xantcha, Sleeper Agent enters under the control of an opponent of your choice.
Xantcha attacks each combat if able and can't attack its owner or planeswalkers its owner controls.
{3}: Xantcha's controller loses 2 life and you draw a card. Any player may activate this ability.

Deathtouch
{2}{B}, {T}: Put a petrification counter on target creature. It gains defender and becomes a colorless artifact in addition to its other types. Its activated abilities can't be activated.

Whenever Xathrid Necromancer or another Human creature you control dies, create a tapped 2/2 black Zombie creature token.

Xenagos Ascended gains trample until end of turn and attacks this turn if able.

Xenagos's Strike deals 4 damage to each player.

Indestructible
As long as your devotion to red and green is less than seven, Xenagos isn't a creature.
At the beginning of combat on your turn, another target creature you control gains haste and gets +X/+X until end of turn, where X is that creature's power.

[+1]: Add X mana in any combination of {R} and/or {G}, where X is the number of creatures you control.
[0]: Create a 2/2 red and green Satyr creature token with haste.
[–6]: Exile the top seven cards of your library. You may put any number of creature and/or land cards from among them onto the battlefield.

{T}: Until your next upkeep, target noncreature artifact becomes an artifact creature with power and toughness each equal to its mana value.

Double strike
Auras you control have exalted.

Xenosquirrels enters with two +1/+1 counters on it.
After you roll a die, you may remove a +1/+1 counter from Xenosquirrels. If you do, increase or decrease the result by 1.

Whenever Xerex Squire attacks, calculate the hypotenuse of another creature you control. Xerex Squire's power and toughness become equal to that number, rounded up, until end of turn. (To calculate a hypotenuse, let A be that creature's power and B be that creature's toughness. Then C = ?(a² + b²). C is the hypotenuse. Or just look up a calculator online.)

Horsemanship
Sacrifice Xiahou Dun, the One-Eyed: Return target black card from your graveyard to your hand. Activate only during your turn, before attackers are declared.

Flying
{B}{R}{G}, {T}: Target player draws a card.

Flying, haste
Whenever Xira, the Golden Sting attacks, put an egg counter on another target creature without an egg counter on it. When that creature dies, if it has an egg counter on it, draw a card and create a 1/1 black Insect creature token with flying.

If you would create one or more Treasure tokens, instead create those tokens plus an additional Treasure token.

{T}: Target creature you control gets +2/+0 until end of turn. Activate only during your turn, before attackers are declared.

Flying
Whenever Xyru Specter deals damage to an opponent, that player discards a card unless they challenge you. If challenged, and you show them two black cards in your hand, they must discard two cards.

All creatures get -3/-3 until end of turn.
You may cast a spell with mana value 3 or less from your hand without paying its mana cost.