New Master of Arms

First strike
Prevent all combat damage that would be dealt by blocking creatures that are tapped.
{1}{W}: Tap target creature blocking New Master of Arms.

Duelists' Convocation International

When Duelists' Convocation International enters the battlefield, choose a 10-digit number at random and write it down.
Whenever you play a land or cast a spell, if it shares a mana value with one or more uncrossed digits in the chosen number, cross out one of those digits and draw a card. Then if all ten digits are crossed out, you win the game.

Plain Walker

Plainswalk
Planeswalkerwalk (This creature can't be blocked as long as defending player controls a planeswalker.)
Whenever Plain Walker deals combat damage to a player or planeswalker, planeswalk. (If you're playing Planechase, proceed to the next plane.)

Don't Worry About It

Enchant card in your hand (This Aura remains on the battlefield. If you play enchanted card or it otherwise leaves your hand, put this Aura into the graveyard.)
Enchanted card costs {1} less to cast.
When you cast enchanted card, copy it.

Knight of Lost Causes

Vigilance
As long as you are way behind, Knight of Lost Causes gets +3/+3 and has indestructible. (You are way behind if, at any point during this turn, an opponent had 10 or more life than you, controlled at least three more creatures than you, or had at least three more cards in hand than you.)

A Girl and Her Dogs

When A Girl and Her Dogs enters the battlefield and at the beginning of your upkeep, create a 1/1 white legendary Dog creature token and name it.
Whenever A Girl and Her Dogs attacks, it gets +1/+1 until end of turn for each legendary creature you control.

Defender of the Queue

Positioning (As this creature enters, lock your creatures in order from left to right for as long as you control a creature with positioning. Each time a creature enters or comes under your control, position it to the left or right of another creature you control.)
Adjacent creatures to the left and right of Defender of the Queue get +1/+1 and have vigilance.

Tax Taker

Whenever an opponent pays a tax from a spell or permanent you control, create a number of Treasure tokens equal to the amount of mana they paid. (This happens each time a spell you control or an ability of a permanent you control causes an opponent to pay extra mana. Cards that can tax opponents include Mana Tithe, Esper Sentinel, and Ghostly Prison.)

TL;DR

Exile target creature if it has any abilities other than keywords. (Flying, protection, and partner are all keywords. See rule 702 for details. Landfall and scry aren't keywords; they're an ability word and a keyword action respectively. Yes, there's a difference.)

Subgoyf

Subgoyf's power and toughness are each equal to the number of different subtypes other than creature types among cards in all graveyards and its toughness is equal to that number plus 1. (Subtypes include but are absolutely not limited to: Plains, Equipment, Aura, Arcane, Jace, Curse, Urza's, Ulamog's, etc.)

Intangible Vibes

All creatures are tokens. (They're considered tokens for spells and abilities. After a creature leaves the battlefield, it ceases to exist.)

You Compleat Me

If your life total is greater than 10, it becomes 10. For the rest of the game, your maximum life total is 10. You get an emblem with "Pay 2 life: Add one mana of any color" and "At the beginning of your upkeep, you draw a card and you lose 1 life."

Pinchy McStingbutt

Deathtouch
Whenever Pinchy McStingbutt deals combat damage to a player, conjure a card named Death of a Thousand Stings, Lethal Sting, or Stinging Shot at random into your hand and reveal it. (Treat conjured cards like cards.)

Wowzer, the Aspirational

Whenever Wowzer, the Aspirational attacks, if you have an {E}, control a Blood, a Clue, a Food, a Map, a Powerstone, and a Treasure, are the monarch, and have the city's blessing and the initiative, you win the game.

Muraganda Eldrazi

Devoid (This card has no color.)
Deworded (This creature counts as having no abilities.)
When you cast this spell, put a primeval counter on target creature. (A creature with a primeval counter loses all abilities and can't gain abilities.)

Who's That Praetor?

Choose one at random. Create a token that's a copy of the chosen card.
• Elesh Norn, Mother of Machines
• Jin-Gitaxias, Progress Tyrant
• Sheoldred, the Apocalypse
• Urabrask, Heretic Praetor
• Vorinclex, Monstrous Raider
• Ebon Praetor

Creepy Crawler

Menace, reach
Whenever Creepy Crawler deals combat damage to a player who is afraid of you, that player discards a card and you draw a card. (An opponent is afraid of you if a Horror, Nightmare, enchantment, or face-down creature you control entered the battlefield or attacked them this turn.)

Bolshack Dragon

Double b̶r̶e̶a̶k̶e̶r̶ strike
While attacking, this creature gets +10̶0̶0̶ power for each f̶i̶r̶e̶ red card in your graveyard.

Naturalize 2

Destroy target artifact, enchantment, emblem, or gameplay tracker. (Trackers include play aids such as dungeons, city's blessing, and monarch. When you destroy it, the associated object or designation is removed from the game.)

Catch of the Day

As Catch of the Day enters the battlefield, choose one for each of the following.
Keyword → Vigilance; ward {3}; or islandwalk.
Whenever this creature attacks → Scry 2; goad target creature an opponent controls; or tap target creature an opponent controls.
Size → 6/2; 4/4; or 2/6.

Noble Ox

Flash
When Noble Ox enters the battlefield, all unblocked creatures attacking you become blocked by Noble Ox.
Noble Ox can block any number of creatures.

Indicate

Halving Season

If an opponent would create one or more tokens, they create half that many of each of those kinds of tokens instead, rounded down.
If an opponent would put one or more counters on a permanent or player, they put half that many of each of those kinds of counters on that permanent or player instead, rounded down.

Zone of Flame

Enchant zone (Battlefield, command, exile, and stack are shared zones. Each player has their own graveyard, hand, and library zones.)
Whenever one or more cards enter or leave enchanted zone, Zone of Flame deals 1 damage to each opponent. (Tokens aren't cards.)

Heart of a Duelist

You may draw cards from anywhere in your library. (You don't get to look at them or reorder them while doing so.)
When Heart of a Duelist enters the battlefield, draw a card.

Blurry Visionary

When Blurry Visionary enters the battlefield, look at the top two cards of your library and put them back-to-back in the same sleeve with either card in front. They become a modal double-faced card for the rest of the game. Then put that card into your hand. (You can play either face of that double-faced card. Make sure to reset it when the game ends.)