Captain Rex Nebula

At the beginning of combat on your turn, choose target nonland permanent you control. Until end of turn, it becomes a Vehicle artifact with base power and toughness each equal to its mana value, and it gains crew 2 and "Crash Land — Whenever this Vehicle deals damage, roll a six-sided die. If the result is equal to this Vehicle's mana value, sacrifice this Vehicle, then it deals that much damage to any target."

Ancient Bronze Dragon

Flying
Whenever Ancient Bronze Dragon deals combat damage to a player, roll a d20. When you do, put X +1/+1 counters on each of up to two target creatures, where X is the result.

Boing!

Return target creature to its owner's hand, then roll a six-sided die. If the result is 3 or less, scry a number of cards equal to the result.

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.

Centaur of Attention

When Centaur of Attention enters the battlefield, 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 Centaur of Attention's stored results.
Centaur of Attention gets +X/+X, where X is the greatest number of stored results on it of the same value.

Cone of Cold

Roll a d20.
1—9 | Tap all creatures your opponents control.
10—19 | Tap all creatures your opponents control. Those creatures don't untap during their controllers' next untap steps.
20 | Tap all creatures your opponents control. Those creatures don't untap during their controllers' next untap steps. Until your next turn, creatures your opponents control enter the battlefield tapped.

"Lifetime" Pass Holder

"Lifetime" Pass Holder enters the battlefield 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.

Bucknard's Everfull Purse

{1}, {T}: Roll a d4 and create a number of Treasure tokens equal to the result. The player to your right gains control of Bucknard's Everfull Purse.

Goblin Morningstar

Equipped creature gets +1/+0 and has trample.
Equip {1}{R}
When Goblin Morningstar enters the battlefield, roll a d20.
1—9 | Create a 1/1 red Goblin creature token.
10—20 | Create a 1/1 red Goblin creature token, then attach Goblin Morningstar to it.

Atomwheel Acrobats

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

Lae'zel's Acrobatics

Exile all nontoken creatures you control, then roll a d20.
1—9 | Return those cards to the battlefield under their owner's control at the beginning of the next end step.
10—20 | Return those cards to the battlefield under their owner's control, then exile them again. Return those cards to the battlefield under their owner's control at the beginning of the next end step.

Delina, Wild Mage

Whenever Delina, Wild Mage attacks, choose target creature you control, then roll a d20.
1—14 | Create a tapped and attacking token that's a copy of that creature, except it's not legendary and it has "At end of combat, exile this creature."
15—20 | Create one of those tokens. You may roll again.

Diviner's Portent

Roll a d20 and add the number of cards in your hand.
1—14 | Draw X cards.
15+ | Scry X, then draw X cards.

Lightfoot Rogue

Sneak Attack — Whenever Lightfoot Rogue attacks, roll a d20.
1—9 | Lightfoot Rogue gains deathtouch until end of turn.
10—19 | It gets +1/+0 and gains deathtouch until end of turn.
20 | It gets +3/+0 and gains first strike and deathtouch until end of turn.

Maddening Hex

Enchant player
Whenever enchanted player casts a noncreature spell, roll a d6. Maddening Hex deals damage to that player equal to the result. Then attach Maddening Hex to another one of your opponents chosen at random.

Bag of Tricks

{4}{G}, {T}: Roll a d8. Reveal cards from the top of your library until you reveal a creature card with mana value equal to the result. Put that card onto the battlefield and the rest on the bottom of your library in a random order.

Contact Other Plane

Roll a d20.
1—9 | Draw two cards.
10—19 | Scry 2, then draw two cards.
20 | Scry 3, then draw three cards.

Earth-Cult Elemental

Siege Monster — When Earth-Cult Elemental enters the battlefield, roll a d20.
1—9 | Each player sacrifices a permanent.
10—19 | Each opponent sacrifices a permanent.
20 | Each opponent sacrifices two permanents.

Farideh's Fireball

Farideh's Fireball deals 5 damage to target creature or planeswalker. Roll a d20.
1—9 | Farideh's Fireball deals 2 damage to each player.
10—20 | Farideh's Fireball deals 2 damage to each opponent.

Aberrant Mind Sorcerer

Psionic Spells — When Aberrant Mind Sorcerer enters the battlefield, choose target instant or sorcery card in your graveyard, then roll a d20.
1—9 | You may put that card on top of your library.
10—20 | Return that card to your hand.

Ancient Brass Dragon

Flying
Whenever Ancient Brass Dragon deals combat damage to a player, roll a d20. When you do, put any number of target creature cards with total mana value X or less from graveyards onto the battlefield under your control, where X is the result.

Arcane Investigator

Search the Room — {5}{U}: Roll a d20.
1—9 | Draw a card.
10—20 | Look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.

Contraband Livestock

Exile target creature, then roll a d20.
1—9 | Its controller creates a 4/4 green Ox creature token.
10—19 | Its controller creates a 2/2 green Boar creature token.
20 | Its controller creates a 0/1 white Goat creature token.

Component Pouch

{T}, Remove a component counter from Component Pouch: Add two mana of different colors.
{T}: Roll a d20.
1—9 | Put a component counter on Component Pouch.
10—20 | Put two component counters on Component Pouch.

Dee Kay, Finder of the Lost

When Dee Kay, Finder of the Lost enters the battlefield, open an Attraction.
Whenever you roll a 2, each opponent loses 1 life and you gain 1 life.
Whenever you roll a 4, you may tap or untap target artifact or creature.
Whenever you roll a 6, return target creature card from your graveyard to your hand.

Djinni Windseer

Flying
When Djinni Windseer enters the battlefield, roll a d20.
1—9 | Scry 1.
10—19 | Scry 2.
20 | Scry 3.

Bag of Devouring

Whenever you sacrifice another nontoken artifact or creature, exile it.
{2}, {T}, Sacrifice another artifact or creature: Draw a card.
{3}, {T}, Sacrifice Bag of Devouring: Roll a d10. Return up to X cards from among cards exiled with Bag of Devouring to their owners' hands, where X is the result.

Hoarding Ogre

Whenever Hoarding Ogre attacks, roll a d20.
1—9 | Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
10—19 | Create two Treasure tokens.
20 | Create three Treasure tokens.

Monoxa, Midway Manager

Whenever you roll a 3 or higher, Monoxa, Midway Manager gains first strike until end of turn. If the roll was 4 or higher, it gains menace until end of turn. If the roll was 5 or higher, it gains lifelink until end of turn.
{6}: Roll a six-sided die.

Complaints Clerk

When Complaints Clerk enters the battlefield, open an Attraction. (Put the top card of your Attraction deck onto the battlefield.)
Whenever you roll a 1, create a 1/1 white Clown Robot artifact creature token.

Myrkul's Edict

Roll a d20.
1—9 | Choose an opponent. That player sacrifices a creature.
10—19 | Each opponent sacrifices a creature.
20 | Each opponent sacrifices a creature with the greatest power among creatures that player controls.

Ebony Fly

Ebony Fly enters the battlefield tapped.
{T}: Add {C}.
{4}: Roll a d6. Until end of turn, you may have Ebony Fly become an X/X Insect artifact creature with flying, where X is the result.
Whenever Ebony Fly attacks, another target attacking creature gains flying until end of turn.

Comet, Stellar Pup

0: Roll a six-sided die.
1 or 2 — [+2], then create two 1/1 green Squirrel creature tokens. They gain haste until end of turn.
3 — [−1], then return a card with mana value 2 or less from your graveyard to your hand.
4 or 5 — Comet, Stellar Pup deals damage equal to the number of loyalty counters on him to a creature or player, then [−2].
6 — [+1], and you may activate Comet, Stellar Pup's loyalty ability two more times this turn.

Journey to the Lost City

At the beginning of your upkeep, exile the top four cards of your library, then roll a d20.
1—9 | You may put a land card from among those cards onto the battlefield.
10—19 | Create a 2/2 green Wolf creature token, then put a +1/+1 counter on it for each creature card among those cards.
20 | Put all permanent cards exiled with Journey to the Lost City onto the battlefield, then sacrifice it.

Herald of Hadar

Circle of Death — {5}{B}: Roll a d20.
1—9 | Each opponent loses 2 life.
10—19 | Each opponent loses 2 life and you gain 2 life.
20 | Each opponent loses 2 life and you gain 2 life. Create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Gale's Redirection

Exile target spell, then roll a d20 and add that spell's mana value.
1—14 | You may cast the exiled card for as long as it remains exiled, and you may spend mana as though it were mana of any color to cast that spell.
15+ | You may cast the exiled card without paying its mana cost for as long as it remains exiled.

Druid of the Emerald Grove

When Druid of the Emerald Grove enters the battlefield, search your library for up to two basic land cards and reveal them, then roll a d20.
9 or less | Put those cards into your hand, then shuffle.
10—19 | Put one of those cards onto the battlefield tapped and the other into your hand, then shuffle.
20+ | Put those cards onto the battlefield tapped, then shuffle.

Ferris Wheel

Visit — Choose target creature that hasn't been phased out with Ferris Wheel. That creature phases out until you roll a 3 or less while rolling to visit your Attractions.

Clowning Around

Create two 1/1 white Clown Robot artifact creature tokens, then roll a six-sided die. If the result is equal to or less than the number of Robots you control, create a 1/1 white Clown Robot artifact creature token.

Dissatisfied Customer

Flying, haste
When Dissatisfied Customer enters the battlefield, roll a six-sided die. If the result is 3 or less, you lose that much life.

Jegantha, the Wellspring

Companion — No card in your starting deck has more than one of the same mana symbol in its mana cost. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
{T}: Add {W}{U}{B}{R}{G}. This mana can't be spent to pay generic mana costs.

Ancient Gold Dragon

Flying
Whenever Ancient Gold Dragon deals combat damage to a player, roll a d20. You create a number of 1/1 blue Faerie Dragon creature tokens with flying equal to the result.

Danse Macabre

Each player sacrifices a nontoken creature. Roll a d20 and add the toughness of the creature you sacrificed this way.
1—14 | Return a creature card put into a graveyard this way to the battlefield under your control.
15+ | Return up to two creature cards put into graveyards this way to the battlefield under your control.

Critical Hit

Target creature gains double strike until end of turn.
When you roll a natural 20, return Critical Hit from your graveyard to your hand. (A natural 20 is a roll that displays 20 on the die.)

Clay Golem

{6}, Roll a d8: Monstrosity X, where X is the result. (If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.)
Berserk — When Clay Golem becomes monstrous, destroy target permanent.

Ancient Silver Dragon

Flying
Whenever Ancient Silver Dragon deals combat damage to a player, roll a d20. Draw cards equal to the result. You have no maximum hand size for the rest of the game.

Iron Mastiff

Whenever Iron Mastiff attacks, roll a d20 for each player being attacked and ignore all but the highest roll.
1—9 | Iron Mastiff deals damage equal to its power to you.
10—19 | Iron Mastiff deals damage equal to its power to defending player.
20 | Iron Mastiff deals damage equal to its power to each opponent.

Chaos Channeler

Wild Magic Surge — Whenever Chaos Channeler attacks, roll a d20.
1—9 | Exile the top card of your library. You may play it this turn.
10—19 | Exile the top two cards of your library. You may play them this turn.
20 | Exile the top three cards of your library. You may play them this turn.