You may have Imposter Mech enter the battlefield as a copy of a creature an opponent controls, except it's a Vehicle artifact with crew 3 and it loses all other card types. Crew 3

Whenever you cast a noncreature spell, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.) Delirium — As long as there are four or more card types among cards in your graveyard, Dragon's Rage Channeler gets +2/+2, has flying, and attacks each combat if able.

({U/P} can be paid with either {U} or 2 life.) Look at target player's hand. Draw a card.

{T}, Sacrifice Mishra's Bauble: Look at the top card of target player's library. Draw a card at the beginning of the next turn's upkeep.

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Indestructible When The One Ring enters the battlefield, if you cast it, you gain protection from everything until your next turn. At the beginning of your upkeep, you lose 1 life for each burden counter on The One Ring. {T}: Put a burden counter on The One Ring, then draw a card for each burden counter on The One Ring.

Avoidance — Whenever you cast a noncreature spell, exile up to one target nonland permanent you control, then return that card to the battlefield under its owner's control.

When Experimental Synthesizer enters or leaves the battlefield, exile the top card of your library. Until end of turn, you may play that card. {2}{R}, Sacrifice Experimental Synthesizer: Create a 2/2 white Samurai creature token with vigilance. Activate only as a sorcery.

Discard your hand, Sacrifice Lion's Eye Diamond: Add three mana of any one color. Activate only as an instant.

Rolling Earthquake deals X damage to each creature without horsemanship and each player.

{1}: Look at the top three cards of your library, then put them back in any order. {T}: Draw a card, then put Sensei's Divining Top on top of its owner's library.

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.) When Ancestral Knowledge enters the battlefield, look at the top ten cards of your library, then exile any number of them and put the rest back on top of your library in any order. When Ancestral Knowledge leaves the battlefield, shuffle your library.

Whenever an opponent casts a spell, you may reveal the top card of your library. If you do, counter that spell if it has the same mana value as the revealed card.

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.) Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}.

Cleave {1}{U} (You may cast this spell for its cleave cost. If you do, remove the words in square brackets.) Return target nonland permanent [you control] to its owner's hand.

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Target player mills three cards. Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

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

Return target nonland permanent to its owner's hand. Then that permanent's controller may sacrifice a land. If the player does, they may copy this spell and may choose a new target for that copy.

Return target nonland permanent you don't control to its owner's hand. Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

If you control a commander, you may cast this spell without paying its mana cost. You may choose new targets for target spell or ability.

Search your library for an artifact or enchantment card, reveal it, then shuffle and put that card on top.

If you control a commander, you may cast this spell without paying its mana cost. Counter target noncreature spell.

Counter target instant or sorcery spell unless its controller pays {1}. Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

If it's not your turn, you may exile a blue card from your hand rather than pay this spell's mana cost. Counter target noncreature spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost. Counter target spell.

({R/P} can be paid with either {R} or 2 life.) Gut Shot deals 1 damage to any target.

Search your library for three cards and reveal them. Target opponent chooses one. Put that card into your hand and the rest into your graveyard. Then shuffle.

As an additional cost to cast this spell, you may exile any number of white cards from your hand. This spell costs {2} less to cast for each card exiled this way. Exile target artifact, creature, or enchantment with mana value X or less.

({U/P} can be paid with either {U} or 2 life.) Counter target spell with mana value 1.

If an opponent cast three or more spells this turn, you may pay {0} rather than pay this spell's mana cost. Exile any number of target spells.

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.

Counter target spell. At the beginning of your next upkeep, pay {3}{U}{U}. If you don't, you lose the game.

Choose one — • Counter target spell if it's blue. • Destroy target permanent if it's blue.

Your opponents can't cast spells this turn.

Return target creature to its owner's hand. Untap up to two lands.

Counter target spell with mana value 2.

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

{T}: Add {C}{C}. Ancient Tomb deals 2 damage to you.

{T}, Pay 1 life, Sacrifice Arid Mesa: Search your library for a Mountain or Plains card, put it onto the battlefield, then shuffle.

{T}, Pay 1 life, Sacrifice Bloodstained Mire: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.

Whenever City of Brass becomes tapped, it deals 1 damage to you. {T}: Add one mana of any color.

When you play another land, sacrifice City of Traitors. {T}: Add {C}{C}.

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

{T}, Pay 1 life: Add {U} or {R}. {1}, {T}, Sacrifice Fiery Islet: Draw a card.

{T}, Pay 1 life, Sacrifice Flooded Strand: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

If Gemstone Caverns is in your opening hand and you're not the starting player, you may begin the game with Gemstone Caverns on the battlefield with a luck counter on it. If you do, exile a card from your hand. {T}: Add {C}. If Gemstone Caverns has a luck counter on it, instead add one mana of any color.

({T}: Add {W} or {U}.) As Hallowed Fountain enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

({T}: Add {U}.)

{T}, Pay 1 life: Add one mana of any color.

{T}, Pay 1 life, Sacrifice Marsh Flats: Search your library for a Plains or Swamp card, put it onto the battlefield, then shuffle.

{T}, Pay 1 life, Sacrifice Misty Rainforest: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

{T}: Add {U}. Channel — {3}{U}, Discard Otawara, Soaring City: Return target artifact, creature, enchantment, or planeswalker to its owner's hand. This ability costs {1} less to activate for each legendary creature you control.

({T}: Add {R} or {W}.)

{T}, Pay 1 life, Sacrifice Polluted Delta: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

{T}, Pay 1 life, Sacrifice Scalding Tarn: Search your library for an Island or Mountain card, put it onto the battlefield, then shuffle.

({T}: Add {U} or {R}.) As Steam Vents enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

{T}: Add {C}. {1}, {T}: Add one mana of any color. {X}, {T}: The Mycosynth Gardens becomes a copy of target nontoken artifact you control with mana value X.

Training Center enters the battlefield tapped unless you have two or more opponents. {T}: Add {U} or {R}.

({T}: Add {W} or {U}.)

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.) I — Urza's Saga gains "{T}: Add {C}." II — Urza's Saga gains "{2}, {T}: Create a 0/0 colorless Construct artifact creature token with 'This creature gets +1/+1 for each artifact you control.'" III — Search your library for an artifact card with mana cost {0} or {1}, put it onto the battlefield, then shuffle.

({T}: Add {U} or {R}.)

{T}, Pay 1 life, Sacrifice Windswept Heath: Search your library for a Forest or Plains card, put it onto the battlefield, then shuffle.

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

Imprint — When Chrome Mox enters the battlefield, you may exile a nonartifact, nonland card from your hand. {T}: Add one mana of any of the exiled card's colors.

When Dockside Extortionist enters the battlefield, create X Treasure tokens, where X is the number of artifacts and enchantments your opponents control. (Treasure tokens are artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

{T}: Add one mana of any color that a land an opponent controls could produce.

Grim Monolith doesn't untap during your untap step. {T}: Add {C}{C}{C}. {4}: Untap Grim Monolith.

Spells cost {1} less to cast.

{1}, {T}: Add {U}{R}.

{1}, {T}: Put a charge counter on Jeweled Amulet. Note the type of mana spent to pay this activation cost. Activate only if there are no charge counters on Jeweled Amulet. {T}, Remove a charge counter from Jeweled Amulet: Add one mana of Jeweled Amulet's last noted type.

{T}, Sacrifice Jeweled Lotus: Add three mana of any one color. Spend this mana only to cast your commander.

{T}, Sacrifice Lotus Petal: Add one mana of any color.

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you. {T}: Add {C}{C}.

Mana Vault doesn't untap during your untap step. At the beginning of your upkeep, you may pay {4}. If you do, untap Mana Vault. At the beginning of your draw step, if Mana Vault is tapped, it deals 1 damage to you. {T}: Add {C}{C}{C}.

{T}: Add one mana of any color among legendary creatures and planeswalkers you control.

If Mox Diamond would enter the battlefield, you may discard a land card instead. If you do, put Mox Diamond onto the battlefield. If you don't, put it into its owner's graveyard. {T}: Add one mana of any color.

Metalcraft — {T}: Add one mana of any color. Activate only if you control three or more artifacts.

Add {R}{R}, then add {R} for each card named Rite of Flame in each graveyard.

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

{T}: Add {C}{C}.

{T}: Add {C}. {T}: Add {U} or {R}. Talisman of Creativity deals 1 damage to you.

Each opponent can't draw more than one card each turn. −2: Look at the top four cards of your library. You may reveal a noncreature, nonland card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Choose one. If you control a commander as you cast this spell, you may choose both instead. • Add {R} for each card in target opponent's hand. • Exile the top three cards of your library. You may play them this turn.

Return target permanent card with mana value 3 or less from your graveyard to the battlefield. If this spell was cast from a graveyard, you may copy this spell and may choose a new target for the copy. Flashback {4}{W} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Each player shuffles their hand and graveyard into their library, then draws seven cards. (Then put Timetwister into its owner's graveyard.)

Sacrifice an artifact. If you do, search your library for an artifact card. If that card's mana value is less than or equal to the sacrificed artifact's mana value, put it onto the battlefield. If it's greater, you may pay {X}, where X is the difference. If you do, put it onto the battlefield. If you don't, put it into its owner's graveyard. Then shuffle.

Each player discards their hand, then draws seven cards.