Wall of Fortune

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

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.

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

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.

Chicken à la King

Whenever a 6 is rolled on a six-sided die, put a +1/+1 counter on each Bird. (You may roll dice only when instructed to.)
Tap an untapped Bird you control: Roll a six-sided die. (Like now.)

Free-Range Chicken

{1}{G}: Roll two six-sided dice. If both results are the same, Free-Range Chicken gets +X/+X until end of turn, where X is that result. If the total of those results is equal to any other total you have rolled this turn for this ability, sacrifice it. (For example, if you roll two 3s, it gets +3/+3. If you roll a 4 and a 2 for this ability later that turn, sacrifice it.)

Hard Hat Area

Whenever you crank Hard Hat Area, roll two six-sided dice. Hard Hat Area assembles a number of Contraptions equal to the difference between those results. (To assemble a Contraption, put the top card of your Contraption deck face up onto one of your sprockets.)

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.

Gift Horse

Whenever you crank Gift Horse, roll two six-sided dice. Create a number of 1/1 red Goblin creature tokens equal to the difference between those results.

Krark's Other Thumb

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

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.

Clam-I-Am

If you roll a 3 on a six-sided die, you may reroll that die.

Urza's Science Fair Project

{2}: Roll a six-sided die. Urza's Science Fair Project gets the indicated result.
1 — It gets -2/-2 until end of turn.
2 — Prevent all combat damage it would deal this turn.
3 — It gains vigilance until end of turn.
4 — It gains first strike until end of turn.
5 — It gains flying until end of turn.
6 — It gets +2/+2 until end of turn.

Very Cryptic Command

Choose two —
• Counter target black-bordered spell.
• Return target creature to its owner's hand.
• Untap each permanent you control with a watermark.
• Roll two six-sided dice. Target player mills X cards, where X is the total of those results.

Growth Spurt

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

Pippa, Duchess of Dice

{2}{G}, {T}: Roll a six-sided die. It becomes a green Die creature token with power and toughness each equal to its result.
{2}{U}, {T}: Reroll any die. (Activate only any time it makes sense.)

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.)

Thud-for-Duds

Whenever you crank Thud-for-Duds, roll two six-sided dice. Thud-for-Duds deals damage to target creature equal to the difference between those results.

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}

Chittering Doom

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

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}

Mother Kangaroo

When this creature enters, roll a six-sided die. Put a number of +1/+1 counters on this creature equal to the result.