Underdome

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to pay Un-costs.

Look at Me, I'm the DCI

Ban a card other than a basic land card for the rest of the match. (All cards with that name in any zone or sideboard are removed from the match.)

Knight of the Hokey Pokey

First strike
{1}{W}, Do the Hokey Pokey: Prevent all damage a source of your choice would deal to Knight of the Hokey Pokey this turn. (To do the Hokey Pokey, choose an arm, a leg, or your whole self and put it in. Put it out. Put it in. Shake it all about. You do the Hokey Pokey! Turn yourself around.)

Frankie Peanuts

At the beginning of your upkeep, you may ask target player a yes-or-no question. If you do, that player answers the question truthfully and abides by that answer if able until end of turn.

Flavor Judge

{T}: Choose target spell or ability that targets a permanent you control. Then ask a person outside the game if the story of what will happen makes sense. If they say no, sacrifice Flavor Judge and counter that spell or ability.

Emcee

Whenever another creature enters, you may stand up and say in a deep, booming voice, "Presenting . . . " and that creature's name. If you do, put a +1/+1 counter on that creature.

Ordinary Pony

When this creature enters, you may exile target non-Horse creature you control that wasn't put onto the battlefield with this ability this turn, then return it to the battlefield under its owner's control.

Humming-

Flying
Whenever you attack with two or more creatures,
Augment {3}{W} ({3}{W}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Strutting Turkey

When this creature enters,
exile target creature card with mana value 2 or less from your graveyard. If it has augment, combine it with a host you control. Otherwise, put it onto the battlefield.

Staying Power

"Until end of turn" and "this turn" effects don't end.

AWOL

Exile target attacking creature. Then remove it from the game. Then put it into the absolutely-removed-from-the-freaking-game-forever zone.

Sword of Dungeons & Dragons

Equipped creature gets +2/+2 and has protection from Rogues and from Clerics.
Whenever equipped creature deals combat damage to a player, create a 4/4 gold Dragon creature token with flying and roll a d20 (a twenty-sided die). If you roll a 20, repeat this process.
Equip {2}

GO TO JAIL

When GO TO JAIL enters, exile target creature an opponent controls until GO TO JAIL leaves the battlefield.
At the beginning of the upkeep of the exiled card's owner, that player rolls two six-sided dice. If they roll doubles, sacrifice GO TO JAIL.

Plains

Look at Me, I'm R&D

As Look at Me, I'm R&D comes into play, choose a number and a second number one higher or one lower than that number.
All instances of the first chosen number on permanents, spells, and cards in any zone are the second chosen number.

Adorable Kitten

When this creature enters, roll a six-sided die. You gain life equal to the result.

Paper Tiger

Creatures named Rock Lobster can't attack or block.

Syr Cadian, Knight Owl

Knightlifelink (Damage dealt by Knights you control also causes you to gain that much life.)
{W}: Syr Cadian, Knight Owl gains vigilance until end of turn. Activate only from sunrise to sunset.
{B}: Syr Cadian, Knight Owl gains flying until end of turn. Activate only from sunset to sunrise.

Old Guard

{W}, {T}: Tap target creature without reminder text. (Reminder text is still any italicized text in parentheses that explains rules you already know.)