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.

Elvish Impersonators

As Elvish Impersonators enters, roll a six-sided die twice. Its base power becomes the first result and its base toughness becomes the second result.

Chittering Doom

Whenever you roll a 4 or higher on a die, create a 1/1 green Squirrel creature token.

Loathsome Troll

{3}{G}: Roll a d20. Activate only if Loathsome Troll is in your graveyard.
1—9 | Put Loathsome Troll on top of your library.
10—19 | Return Loathsome Troll to your hand.
20 | Return Loathsome Troll to the battlefield tapped.

The Deck of Many Things

{2}, {T}: Roll a d20 and subtract the number of cards in your hand. If the result is 0 or less, discard your hand.
1—9 | Return a card at random from your graveyard to your hand.
10—19 | Draw two cards.
20 | Put a creature card from any graveyard onto the battlefield under your control. When that creature dies, its owner loses the game.

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.

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}

Krark's Other Thumb

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

Song of Inspiration

Choose up to two target permanent cards in your graveyard. Roll a d20 and add the total mana value of those cards.
1—14 | Return those cards to your hand.
15+ | Return those cards to your hand. You gain life equal to their total mana value.

Selfie Preservation

Search your library for a basic land card and reveal it. If there's a tree in its art, put it onto the battlefield tapped. Otherwise, put it into your hand. Then shuffle.

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.

"Lifetime" Pass Holder

"Lifetime" Pass Holder enters tapped.
When "Lifetime" Pass Holder dies, open an Attraction.
Whenever you roll to visit your Attractions, if you roll a 6, you may return "Lifetime" Pass Holder from your graveyard to the battlefield.

Family's Favor

Whenever you attack, put a shield counter on target attacking creature. Until end of turn, it gains "Whenever this creature deals combat damage to a player, remove a shield counter from it. If you do, draw a card." (If a creature with a shield counter on it would be dealt damage or destroyed, remove a shield counter from it instead.)

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}

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.)

Growth Spurt

Roll a six-sided die. Target creature gets +X/+X until end of turn, where X is the result.

Snickering Squirrel

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