The Grand Calcutron

The Grand Calcutron can be your commander.
When The Grand Calcutron enters, each player's hand becomes a program (an ordered row of revealed cards).
Players can only play the first card of their program.
If a card would be put into a player's hand from anywhere, that player reveals it and places it anywhere within their program instead.
At the beginning of each player's end step, if that player's program has fewer than five cards, they draw cards equal to the difference.

Jamming Device

Whenever you crank Jamming Device, creatures target player controls get -1/-1 until end of turn.

Clock of DOOOOOOOOOOOOM!

{4}, {T}: Move the CRANK! counter to your Contraption deck's next sprocket and crank any number of that sprocket's Contraptions.

The World Tree

The World Tree enters tapped.
{T}: Add {G}.
As long as you control six or more lands, lands you control have "{T}: Add one mana of any color."
{W}{W}{U}{U}{B}{B}{R}{R}{G}{G}, {T}, Sacrifice The World Tree: Search your library for any number of God cards, put them onto the battlefield, then shuffle.

Volcanic Torrent

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
Volcanic Torrent deals X damage to each creature and planeswalker your opponents control, where X is the number of spells you've cast this turn.

Aurora Phoenix

Flying
Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
Whenever you cast a spell with cascade, return Aurora Phoenix from your graveyard to your hand.

Conjurer's Closet

At the beginning of your end step, you may exile target creature you control, then return that card to the battlefield under your control.

Deny Reality

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
Return target permanent to its owner's hand.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

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.)

Steamflogger of the Month

When Steamflogger of the Month enters, it assembles a Contraption for each Contraption you control. (To assemble a Contraption, put the top card of your Contraption deck face up onto one of your sprockets.)

Faerie Aerie

Whenever you crank Faerie Aerie, create two 1/1 blue Faerie Spy creature tokens with flying, haste, and "Whenever this creature deals combat damage to a player, draw a card." Exile them at the beginning of the next end step.

The Prismatic Bridge

At the beginning of your upkeep, reveal cards from the top of your library until you reveal a creature or planeswalker card. Put that card onto the battlefield and the rest on the bottom of your library in a random order.

Esika, God of the Tree

Vigilance
{T}: Add one mana of any color.
Other legendary creatures you control have vigilance and "{T}: Add one mana of any color."

Esika, God of the Tree // The Prismatic Bridge

Rapid Prototyper

Whenever you crank Rapid Prototyper, create an X/X colorless Construct artifact creature token, where X is the number of artifacts you control.

Midlife Upgrade

As an additional cost to cast this spell, sacrifice X Contraptions.
Assemble X plus one Contraptions. (To assemble a Contraption, put the top card of your Contraption deck face up onto one of your sprockets.)

Eladamri's Call

Search your library for a creature card, reveal that card, put it into your hand, then shuffle.

Etali, Primal Storm

Whenever Etali attacks, exile the top card of each player's library, then you may cast any number of spells from among those cards without paying their mana costs.

Orzhov Signet

Sundering Fork

Whenever you crank Sundering Fork, destroy target artifact.

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.

Neural Network

Whenever you crank Neural Network, gain control of target creature an opponent controls with power less than or equal to the number of creature cards in its controller's graveyard until end of turn. Untap that creature. It gains haste until end of turn.

Simic Signet

Etherium-Horn Sorcerer

{1}{U}{R}: Return Etherium-Horn Sorcerer to its owner's hand.
Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)

Mizzix's Mastery

Exile target card that's an instant or sorcery from your graveyard. For each card exiled this way, copy it, and you may cast the copy without paying its mana cost. Exile Mizzix's Mastery.
Overload {5}{R}{R}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Record Store

Whenever you crank Record Store, look at the top X cards of your library, where X is the number of artifacts you control. Put one of those cards into your hand and the rest on the bottom of your library in a random order.

Clocknapper

When Clocknapper enters, choose beginning phase, first main phase, combat phase, postcombat main phase, or ending phase. Steal that phase from target player during their next turn. (That phase occurs as though it's your turn instead.)

Genesis Ultimatum

Look at the top five cards of your library. Put any number of permanent cards from among them onto the battlefield and the rest into your hand. Exile Genesis Ultimatum.

Natural Reclamation

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
Destroy target artifact or enchantment.

Goblin Tutor

Roll a six-sided die. If you roll a 1, Goblin Tutor has no effect. Otherwise, search your library for the indicated card, reveal it, put it into your hand, then shuffle.
2 — A card named Goblin Tutor
3 — An enchantment
4 — An artifact
5 — A creature
6 — An instant or sorcery

Rakdos Signet

Yet Another Aether Vortex

All creatures have haste.
Players play with the top card of their libraries revealed.
Noninstant, nonsorcery cards on top of a library are on the battlefield under their owner's control in addition to being in that library.

Richard Garfield, Ph.D.

You may play cards as though they were other cards of your choice with the same mana cost. You can't choose the same card twice. (Mana cost includes color.)

Boros Signet

Izzet Signet

Ruinous Ultimatum

Destroy all nonland permanents your opponents control.

Sakashima's Protege

Flash
Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
You may have Sakashima's Protege enter as a copy of any permanent that entered this turn.

Ethersworn Sphinx

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Flying
Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card with lesser mana value. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)

Goblin Slingshot

Whenever you crank Goblin Slingshot, creatures you control get +2/+0 and gain trample until end of turn.

Maelstrom Wanderer

Creatures you control have haste.
Cascade, cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order. Then do it again.)

Split Screen

When Split Screen enters, shuffle your library and deal it into four libraries. If anything refers to your library, choose one of your libraries for it.
Play with your libraries' top cards revealed.
When Split Screen leaves the battlefield, shuffle your libraries together.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Imoti, Celebrant of Bounty

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
Spells you cast with mana value 6 or greater have cascade.

Dispatch Dispensary

Whenever you crank Dispatch Dispensary, create a 2/2 black Rogue creature token with menace.

Mosswort Bridge

Hideaway 4 (When this land enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.)
Mosswort Bridge enters tapped.
{T}: Add {G}.
{G}, {T}: You may play the exiled card without paying its mana cost if creatures you control have total power 10 or greater.

Eerie Interlude

Exile any number of target creatures you control. Return those cards to the battlefield under their owner's control at the beginning of the next end step.

Extinction Event

Choose odd or even. Exile each creature with mana value of the chosen quality. (Zero is even.)

Emergent Ultimatum

Search your library for up to three monocolored cards with different names and exile them. An opponent chooses one of those cards. Shuffle that card into your library. You may cast the other cards without paying their mana costs. Exile Emergent Ultimatum.

Spinerock Knoll

Hideaway 4 (When this land enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.)
Spinerock Knoll enters tapped.
{T}: Add {R}.
{R}, {T}: You may play the exiled card without paying its mana cost if an opponent was dealt 7 or more damage this turn.

Thassa, Deep-Dwelling

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature.
At the beginning of your end step, exile up to one other target creature you control, then return that card to the battlefield under your control.
{3}{U}: Tap another target creature.

Joyride Rigger

When Joyride Rigger enters, it assembles a Contraption. (Put the top card of your Contraption deck face up onto one of your sprockets.)

Yidris, Maelstrom Wielder

Trample
Whenever Yidris, Maelstrom Wielder deals combat damage to a player, as you cast spells from your hand this turn, they gain cascade. (When you cast the spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)

Spell Suck

Counter target spell, then assemble a Contraption. (Put the top card of your Contraption deck face up onto one of your sprockets.)

Pet Project

Whenever you crank Pet Project, put target creature card from an opponent's graveyard onto the battlefield under your control.

Captured Sunlight

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
You gain 4 life.

First Pick

Destroy target artifact or enchantment. Assemble a Contraption. (Put the top card of your Contraption deck face up onto one of your sprockets.)

Shardless Agent

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)

Stolen Strategy

At the beginning of your upkeep, exile the top card of each opponent's library. Until end of turn, you may cast spells from among those exiled cards, and you may spend mana as though it were mana of any color to cast those spells.

Bituminous Blast

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
Bituminous Blast deals 4 damage to target creature.

Urza, Academy Headmaster

+1: Head to AskUrza.com and click +1.
−1: Head to AskUrza.com and click -1.
−6: Head to AskUrza.com and click -6.

Overt Operative

Menace
Whenever Overt Operative deals combat damage to a player, it assembles a Contraption. (Put the top card of your Contraption deck face up onto one of your sprockets.)

Guest List

Whenever you crank Guest List, target creature gets -X/-X until end of turn, where X is the number of creature cards in its controller's graveyard.

Widget Contraption

Whenever you crank Widget Contraption, it assembles a Contraption. (Put the top card of your Contraption deck face up onto one of your sprockets.)

Apex Devastator

Cascade, cascade, cascade, cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order. Multiple instances of cascade each trigger separately.)

Soulherder

Whenever a creature is exiled from the battlefield, put a +1/+1 counter on Soulherder.
At the beginning of your end step, you may exile another target creature you control, then return that card to the battlefield under its owner's control.

Nightmare Unmaking

Choose one —
• Exile each creature with power greater than the number of cards in your hand.
• Exile each creature with power less than the number of cards in your hand.

Wastes

Azorius Signet

Nettlecyst

Living weapon (When this Equipment enters, create a 0/0 black Phyrexian Germ creature token, then attach this to it.)
Equipped creature gets +1/+1 for each artifact and/or enchantment you control.
Equip {2}

Incite Insight

Assemble X Contraptions. (To assemble a Contraption, put the top card of your Contraption deck face up onto one of your sprockets.)

Crafty Octopus

When this creature enters, this creature assembles a Contraption. (Put the top card of your Contraption deck face up onto one of your sprockets.)

Averna, the Chaos Bloom

As you cascade, you may put a land card from among the exiled cards onto the battlefield tapped. (Do this after the last card is exiled but before deciding whether to cast a nonland card.)

Meddling Kids

As Meddling Kids enters, choose a word with four or more letters.
Spells with the chosen word in their text box can't be cast.

Gnomeball Machine

Whenever you crank Gnomeball Machine, create two 1/1 colorless Gnome artifact creature tokens.

Brago, King Eternal

Flying
Whenever Brago, King Eternal deals combat damage to a player, exile any number of target nonland permanents you control, then return those cards to the battlefield under their owner's control.

Steady-Handed Mook

Deathtouch
When Steady-Handed Mook enters, it assembles a Contraption. (Put the top card of your Contraption deck face up onto one of your sprockets.)

Wrench-Rigger

When Wrench-Rigger enters, it assembles a Contraption. (Put the top card of your Contraption deck face up onto one of your sprockets.)

Nassari, Dean of Expression

At the beginning of your upkeep, exile the top card of each opponent's library. Until end of turn, you may cast spells from among those exiled cards, and you may spend mana as though it were mana of any color to cast those spells.
Whenever you cast a spell from exile, put a +1/+1 counter on Nassari, Dean of Expression.

Uvilda, Dean of Perfection

{T}: You may exile an instant or sorcery card from your hand and put three hone counters on it. It gains "At the beginning of your upkeep, if this card is exiled, remove a hone counter from it" and "When the last hone counter is removed from this card, if it's exiled, you may cast it. It costs {4} less to cast this way."

Uvilda, Dean of Perfection // Nassari, Dean of Expression

Garbage Elemental

Last strike (This creature deals combat damage after creatures without last strike.)
Battalion — Whenever Garbage Elemental and at least two other creatures attack, target creature can't block this turn.

Steamfloggery

Roll a six-sided die. Assemble a number of Contraptions equal to the result. (To assemble a Contraption, put the top card of your Contraption deck face up onto one of your sprockets.)

Windbrisk Heights

Hideaway 4 (When this land enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.)
Windbrisk Heights enters tapped.
{T}: Add {W}.
{W}, {T}: You may play the exiled card without paying its mana cost if you attacked with three or more creatures this turn.

Golos, Tireless Pilgrim

When Golos, Tireless Pilgrim enters, you may search your library for a land card, put that card onto the battlefield tapped, then shuffle.
{2}{W}{U}{B}{R}{G}: Exile the top three cards of your library. You may play them this turn without paying their mana costs.

Topsy Turvy

The phases of each player's turn are reversed. (The phases are, in reverse order, ending, second main, combat, first main, and beginning.)
As long as there are more than two players in the game, the turn order is reversed.

Dimir Signet

Deadly Poison Sampler

Whenever you crank Deadly Poison Sampler, until end of turn, target creature gains "Whenever this creature deals combat damage to a player, destroy target creature that player controls."

Slaying Mantis

Just a second (As long as this spell is on the stack, players can't move permanents.)
Slaying Mantis enters by being thrown from a distance of at least three feet.
When Slaying Mantis enters, it fights each creature an opponent controls that it touched as it entered.

Cramped Bunker

At the beginning of each opponent's upkeep, that player moves a permanent they control to touch Cramped Bunker and no other permanents. If the player can't, destroy each permanent they control that isn't touching Cramped Bunker, then sacrifice it.

Semester's End

Exile any number of target creatures and/or planeswalkers you control. At the beginning of the next end step, return each of them to the battlefield under its owner's control. Each of them enters with an additional +1/+1 counter on it if it's a creature and an additional loyalty counter on it if it's a planeswalker.

Duplication Device

Whenever you crank Duplication Device, until end of turn, target creature becomes a copy of any creature on the battlefield, except it's an artifact in addition to its other types.

Throes of Chaos

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)

Ephemerate

Exile target creature you control, then return it to the battlefield under its owner's control.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)