Vegetation Abomination

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

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}

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}

Border Guardian

Whenever you cast a silver-bordered spell, put a +1/+1 counter on Border Guardian.
Whenever you cast a black-bordered spell, Border Guardian can't be blocked this turn.
Whenever you cast a white-bordered spell, Border Guardian gains double strike until end of turn.

Urza's Hot Tub

{2}, Discard a card: Search your library for a card that shares a complete word in its name with the discarded card, reveal it, put it into your hand, then shuffle.

Ashnod's Coupon

{T}, Sacrifice Ashnod's Coupon: Target player gets you target drink. You pay any costs for the drink.

Do-It-Yourself Seraph

Flying
Whenever Do-It-Yourself Seraph attacks, you may search your library for an artifact card, exile it, then shuffle.
Do-It-Yourself Seraph has the text box of each card exiled with Do-It-Yourself Seraph in addition to its own.

Kindly Cognician

Spells you cast that refer to artifacts or Contraptions in their rules text cost {1} less to cast.

My First Tome

{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 they guessed wrong, you draw a card.

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.

Letter Bomb

When Letter Bomb enters, sign it and shuffle it into target player's library. That player reveals each card they draw until they draw Letter Bomb. When that player draws Letter Bomb, it deals 19½ damage to them.

Wall of Fortune

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

Knight of the Kitchen Sink

First strike, protection from black borders (Nothing with a black border can block, target, deal damage to, or attach to this creature.)

World-Bottling Kit

{5}, Sacrifice World-Bottling Kit: Choose a Magic set. Exile all permanents with that set's expansion symbol except for basic lands.

Blue Ribbon

When Blue Ribbon enters, ask a person outside the game which creature you control is most deserving of a blue ribbon. Attach Blue Ribbon to that creature.
Equipped creature has best in show. (Whenever another creature becomes the target of a spell or ability you control, you may copy that spell or ability. If you do, the copy targets this creature.)
Equip {3}

Bronze Calendar

Spells you cast cost {1} less to cast.
You must speak in a voice other than your normal voice.
When you speak in your normal voice, sacrifice Bronze Calendar.

Mirror Mirror

Mirror Mirror enters tapped.
{7}, {T}, Sacrifice Mirror Mirror: Choose target player. At the beginning of the next end step, exchange life totals with that player, exchange control of all permanents you and that player control, and exchange cards in your hands, cards in your libraries, and cards in your graveyards.

Krark's Other Thumb

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

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}

Strength-Testing Hammer

Whenever equipped creature attacks, roll a six-sided die. That creature gets +X/+0 until end of turn, where X is the result. Then if it has the greatest power or is tied for greatest power among creatures on the battlefield, draw a card.
Equip {3}

Park Map

{1}, Sacrifice Park Map: Search your library for a land card that doesn't have the same art as a permanent you control, reveal it, put it into your hand, then shuffle.

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.

Killer Cosplay

Whenever Killer Cosplay becomes attached to a creature, choose a creature card name with an identical mana cost. That creature becomes a copy of the card with the chosen name until Killer Cosplay becomes unattached from it.
Equip {3}

Paper Tiger

Creatures named Rock Lobster can't attack or block.

Scissors Lizard

Creatures named Paper Tiger can't attack or block.

Jack-in-the-Mox

{T}: Roll a six-sided die. This ability has the indicated effect.
1 — Sacrifice Jack-in-the-Mox and you lose 5 life.
2 — Add {W}.
3 — Add {U}.
4 — Add {B}.
5 — Add {R}.
6 — Add {G}.

Socketed Sprocketer

{T}: Uninstall all results from Socketed Sprocketer, then roll a six-sided die. Install the result on Socketed Sprocketer. (Put the die on this card.)
You may uninstall a result from Socketed Sprocketer to use it for a die you rolled.
Uninstall a 6 from Socketed Sprocketer: Draw a card.

Rock Lobster

Creatures named Scissors Lizard can't attack or block.

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.

Arteeoh, Dread Scavenger

Flying, deathtouch
Whenever Arteeoh deals combat damage to a player, you may exchange control of two other target artifacts. When you do, create a token that's a copy of target artifact you don't control, except it's a 1/1 green Squirrel creature token in addition to its other colors and types.

Non-Human Cannonball

When Non-Human Cannonball dies, roll a six-sided die. If the result is 4 or less, Non-Human Cannonball deals that much damage to you.