Steel Squirrel

Whenever you roll a 5 or higher on a die, Steel Squirrel gets +X/+X until end of turn, where X is the result.
{6}: Roll a six-sided die.

Ground Pounder

{3}{G}: Roll a six-sided die. Ground Pounder gets +X/+X until end of turn, where X is the result.
Whenever you roll a 5 or higher on a die, Ground Pounder gains trample until end of turn.

Proper Laboratory Attire

Equipped creature gets +2/+1 and has protection from die rolls. (Nothing that lets a player roll a die can block, target, deal damage to, or attach to equipped creature.)
Equip {2}

Willing Test Subject

Reach
Whenever you roll a 4 or higher on a die, put a +1/+1 counter on Willing Test Subject.
{6}: Roll a six-sided die.

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}

Jackknight

Whenever another artifact you control enters, put a +1/+1 counter on Jackknight. If that artifact is a Contraption, Jackknight gains lifelink until end of turn.

As Luck Would Have It

Hexproof
Whenever you roll a die, put a number of luck counters on As Luck Would Have It equal to the result. Then if there are 100 or more luck counters on As Luck Would Have It, you win the game. (Count both rolls if you reroll a die.)

Lobe Lobber

Equipped creature has "{T}: This creature deals 1 damage to target player or planeswalker. Roll a six-sided die. On a 5 or higher, untap it."
Equip {2}

Amateur Auteur

Sacrifice Amateur Auteur: Destroy target enchantment.

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.

Garbage Elemental

Last strike (This creature deals combat damage after creatures without last strike.)
Battalion — Whenever Garbage Elemental and at least two other creatures attack, target creature can't block this turn.

Three-Headed Goblin

Triple strike (This creature deals first-strike, regular, and last-strike combat damage.)

Wall of Fortune

Defender
You may tap an untapped Wall you control to have any player reroll a die that player rolled.

Everythingamajig

{T}: Add one mana of any color.
{1}, {T}: Say the flavor text on a card in your hand. Target opponent guesses that card's name. You may reveal that card. If you do and your opponent guessed wrong, draw a card.
{8}, {T}: Everythingamajig deals 12 damage to target creature.

Painiac

At the beginning of your upkeep, roll a six-sided die. Painiac gets +X/+0 until end of turn, where X is the result.

Inhumaniac

At the beginning of your upkeep, roll a six-sided die. On a 3 or 4, put a +1/+1 counter on Inhumaniac. On a 5 or higher, put two +1/+1 counters on it. On a 1, remove all +1/+1 counters from Inhumaniac.

Target Minotaur

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Hammer Helper

Gain control of target creature until end of turn. Untap that creature and roll a six-sided die. Until end of turn, it gains haste and gets +X/+0, where X is the result.

Sly Spy

Whenever Sly Spy deals combat damage to a player, roll a six-sided die. That player loses life equal to the result.

Box of Free-Range Goblins

Roll a six-sided die. Create a number of 1/1 red Goblin creature tokens equal to the result.

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.

Extremely Slow Zombie

Last strike (This creature deals combat damage after creatures without last strike.)

Just Desserts

Just Desserts deals π damage to target creature. (π is the ratio of a circle's circumference to its diameter. (It's a smidgen more than 3.))

Buzzing Whack-a-Doodle

As Buzzing Whack-a-Doodle enters, you and an opponent each secretly choose Whack or Doodle. Then those choices are revealed. If the choices match, Buzzing Whack-a-Doodle has that ability. Otherwise, it has Buzz.
• Whack — {T}: Target player loses 2 life.
• Doodle — {T}: You gain 3 life.
• Buzz — {2}, {T}: Draw a card.

Baron Von Count

Baron Von Count enters with a doom counter on "5."
Whenever you cast a spell with the indicated numeral in its mana cost, text box, power, or toughness, move the doom counter one numeral to the left.
When the doom counter moves from "1," destroy target player and put that doom counter on "5."

Hangman

As Hangman enters, secretly note a word with six to eight letters.
{1}: Target player who doesn't control Hangman guesses the noted word or an unguessed letter in that word. If they guess wrong, put a +1/+1 counter on Hangman. Any player may activate this ability.
When a player guesses the noted word or all of its letters, sacrifice Hangman.

Krark's Other Thumb

If you would roll a die, instead roll two of those dice and ignore one of those results.

The Big Idea

{2}{B/R}{B/R}, {T}: Roll a six-sided die. Create a number of 1/1 red Brainiac creature tokens equal to the result.
Tap three untapped Brainiacs you control: The next time you would roll a six-sided die, instead roll two six-sided dice and use the total of those results.

Crow Storm

Create a 1/2 blue Bird creature token with flying named Storm Crow.
Storm (When you cast this spell, copy it for each spell cast before it this turn.)

More or Less

Add or subtract 1 or one from a number or number word on target spell or permanent until end of turn.

Hydradoodle

As Hydradoodle enters, roll X six-sided dice. Hydradoodle enters with a number of +1/+1 counters on it equal to the total of those results.
Reach, trample

Super-Duper Death Ray

Trample (This spell can deal excess damage to its target's controller.)
Super-Duper Death Ray deals 4 damage to target creature.

Earl of Squirrel

Squirrellink (Damage dealt by this creature also causes you to create that many 1/1 green Squirrel creature tokens.)
Creature tokens you control are Squirrels in addition to their other creature types.
Other Squirrels you control get +1/+1.

Grusilda, Monster Masher

Combined, enchanted, and equipped creatures you control have menace.
{3}{B}{R}, {T}: Put two target creature cards from graveyards onto the battlefield combined into one creature under your control. (Its power is equal to their total power, its toughness is equal to their total toughness, and it has their names, mana costs, types, text boxes, etc.)

Time Out

Roll a six-sided die. Put target nonland permanent into its owner's library just beneath the top X cards of that library, where X is the result.

Mad Science Fair Project

{T}: Roll a six-sided die. On a 3 or lower, target player adds {C}. Otherwise, that player adds one mana of any color they choose.

Snickering Squirrel

You may tap Snickering Squirrel to increase the result of a die any player rolled by 1.