Atomwheel Acrobats

Whenever you roll a 1 or 2, put that many +1/+1 counters on this creature.
{2}{G}: Roll a six-sided die.

Sylvan Shepherd

Vigilance
Whenever this creature attacks, roll a d20.
1—9 | You gain 1 life.
10—19 | You gain 2 life.
20 | You gain 5 life.

Strategy, Schmategy

Roll a six-sided die. Strategy, Schmategy has the indicated effect.
1 — Do nothing.
2 — Destroy all artifacts.
3 — Destroy all lands.
4 — Strategy, Schmategy deals 3 damage to each creature and each player.
5 — Each player discards their hand and draws seven cards.
6 — Repeat this process two more times.

Vrondiss, Rage of Ancients

Enrage — Whenever Vrondiss is dealt damage, you may create a 5/4 red and green Dragon Spirit creature token with "When this token deals damage, sacrifice it."
Whenever you roll one or more dice, you may have Vrondiss deal 1 damage to itself.

Forest

Neverwinter Hydra

As this creature enters, roll X d6. It enters with a number of +1/+1 counters on it equal to the total of those results.
Trample
Ward {4} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {4}.)

Mountain

The Space Family Goblinson

The Space Family Goblinson has trample as long as you've rolled three or more dice this turn.
Whenever you roll a die, put a +1/+1 counter on The Space Family Goblinson.

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}

Hydradoodle

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

Vegetation Abomination

Deathtouch
{T}, Sacrifice this creature: Roll a six-sided die. You gain life equal to the result.

Wild Endeavor

Roll two d4 and choose one result. Create a number of 3/3 green Beast creature tokens equal to that result. Then search your library for a number of basic land cards equal to the other result, put them onto the battlefield tapped, then shuffle.

Circuits Act

Roll three six-sided dice. For each different result, create a 1/1 white Clown Robot artifact creature token.

Goblin Bookie

{R}, {T}: Reflip any coin or reroll any die. (Activate only any time it makes sense.)

Sword of Hours

Whenever equipped creature attacks, put a +1/+1 counter on it.
Whenever equipped creature deals combat damage, roll a d12. If the result is greater than the damage dealt or the result is 12, double the number of +1/+1 counters on that creature.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Wyll's Reversal

Choose target spell or ability with one or more targets. Roll a d20 and add the greatest power among creatures you control.
1—14 | You may choose new targets for that spell or ability.
15+ | You may choose new targets for that spell or ability. Then copy it. You may choose new targets for the copy.

Chittering Doom

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

Centaur of Attention

When this creature enters, roll five six-sided dice and store those results on it.
At the beginning of combat on your turn, you may reroll any number of this creature's stored results.
This creature gets +X/+X, where X is the greatest number of stored results on it of the same value.

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.

Chicken Egg

At the beginning of your upkeep, roll a six-sided die. If you roll a 6, sacrifice this creature and create a 4/4 red Giant Bird creature token.

Spark Fiend

When this creature enters, roll two six-sided dice. If you rolled 2, 3, or 12, sacrifice this creature. If you rolled 7 or 11, don't roll dice for this creature during any of your following upkeeps. If you rolled any other total, note that total.
At the beginning of your upkeep, roll two six-sided dice. If you rolled 7, sacrifice this creature. If you roll the noted total, don't roll dice for this creature during any of your following upkeeps. Otherwise, do nothing.

Wyll, Blade of Frontiers

If you would roll one or more dice, instead roll that many dice plus one and ignore the lowest roll.
Whenever you roll one or more dice, put a +1/+1 counter on Wyll.
Choose a Background (You can have a Background as a second commander.)

Brazen Dwarf

Whenever you roll one or more dice, this creature deals 1 damage to each opponent.