Reveal the top X cards of your library. Put all land cards from among them onto the battlefield tapped and the rest on the bottom of your library in a random order.
Spell mastery -- If there are two or more instant and/or sorcery cards in your graveyard, untap those lands.
{X}{U}{U}{U}
Blue Sun's Zenith
Instant
Target player draws X cards. Shuffle Blue Sun's Zenith into its owner's library.
{2}{G}
Branching Evolution
Enchantment
If one or more +1/+1 counters would be put on a creature you control, twice that many +1/+1 counters are put on that creature instead.
{X}{G}
Capricopian
Creature - Goat Hydra
Capricopian enters the battlefield with X +1/+1 counters on it.
{2}: Put a +1/+1 counter on Capricopian, then you may reselect which player Capricopian is attacking. Only the player Capricopian is attacking may activate this ability and only during the declare attackers step. (It can't attack its controller.)
0 /
0
--
Command Tower
Land
{T}: Add one mana of any color in your commander's color identity.
{3}
Commander's Sphere
Artifact
{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.
{X}{U}
Condescend
Instant
Counter target spell unless its controller pays {X}. Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)
{2}{B}{G}
Corpsejack Menace
Creature - Fungus
If one or more +1/+1 counters would be put on a creature you control, twice that many +1/+1 counters are put on it instead.
4 /
4
{U}{U}
Counterspell
Instant
Counter target spell.
{2}{G}
Cultivate
Sorcery
Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.
--
Dismal Backwater
Land
Dismal Backwater enters the battlefield tapped.
When Dismal Backwater enters the battlefield, you gain 1 life.
{T}: Add {U} or {B}.
{X}{2}{U}
Drown in Dreams
Instant
Choose one. If you control a commander as you cast this spell, you may choose both.
• Target player draws X cards.
• Target player mills twice X cards.
{2}{G}
Elemental Bond
Enchantment
Whenever a creature with power 3 or greater enters the battlefield under your control, draw a card.
{3}
Elementalist's Palette
Artifact
Whenever you cast a spell with {X} in its mana cost, put two charge counters on Elementalist's Palette.
{T}: Add one mana of any color.
{T}: Add {C} for each charge counter on Elementalist's Palette. Spend this mana only on costs that contain {X}.
{X}{B}{B}
Exsanguinate
Sorcery
Each opponent loses X life. You gain life equal to the life lost this way.
{X}{G}
Feral Hydra
Creature - Hydra Beast
Feral Hydra enters the battlefield with X +1/+1 counters on it.
{3}: Put a +1/+1 counter on Feral Hydra. Any player may activate this ability.
0 /
0
{X}{U}{U}
Finale of Revelation
Sorcery
Draw X cards. If X is 10 or more, instead shuffle your graveyard into your library, draw X cards, untap up to five lands, and you have no maximum hand size for the rest of the game.
Exile Finale of Revelation.
--
Forest
Basic Land - Forest
({T}: Add {G}.)
--
Forest
Basic Land - Forest
({T}: Add {G}.)
--
Forest
Basic Land - Forest
({T}: Add {G}.)
--
Forest
Basic Land - Forest
({T}: Add {G}.)
--
Forest
Basic Land - Forest
({T}: Add {G}.)
--
Forest
Basic Land - Forest
({T}: Add {G}.)
--
Forest
Basic Land - Forest
({T}: Add {G}.)
--
Forest
Basic Land - Forest
({T}: Add {G}.)
--
Forest
Basic Land - Forest
({T}: Add {G}.)
--
Forest
Basic Land - Forest
({T}: Add {G}.)
--
Forest
Basic Land - Forest
({T}: Add {G}.)
--
Forest
Basic Land - Forest
({T}: Add {G}.)
--
Forest
Basic Land - Forest
({T}: Add {G}.)
--
Forest
Basic Land - Forest
({T}: Add {G}.)
--
Forest
Basic Land - Forest
({T}: Add {G}.)
{3}{G}{G}{G}
Gargos, Vicious Watcher
Legendary Creature - Hydra
Vigilance
Hydra spells you cast cost {4} less to cast.
Whenever a creature you control becomes the target of a spell, Gargos, Vicious Watcher fights up to one target creature you don't control.
8 /
7
{2}{G}
Garruk's Uprising
Enchantment
When Garruk's Uprising enters the battlefield, if you control a creature with power 4 or greater, draw a card.
Creatures you control have trample. (They can deal excess combat damage to the player or planeswalker they're attacking.)
Whenever a creature with power 4 or greater enters the battlefield under your control, draw a card.
{X}{G}{G}
Genesis Hydra
Creature - Plant Hydra
When you cast this spell, reveal the top X cards of your library. You may put a nonland permanent card with mana value X or less from among them onto the battlefield. Then shuffle the rest into your library.
Genesis Hydra enters the battlefield with X +1/+1 counters on it.
0 /
0
{1}{B}{G}
Grakmaw, Skyclave Ravager
Legendary Creature - Hydra Horror
Grakmaw, Skyclave Ravager enters the battlefield with three +1/+1 counters on it.
Whenever another creature you control dies, if it had a +1/+1 counter on it, put a +1/+1 counter on Grakmaw.
When Grakmaw dies, create an X/X black and green Hydra creature token, where X is the number of +1/+1 counters on Grakmaw.
0 /
0
{G}{U}
Growth Spiral
Instant
Draw a card. You may put a land card from your hand onto the battlefield.
{G}
Hardened Scales
Enchantment
If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on it instead.
{3}{U}
Herald of Secret Streams
Creature - Merfolk Warrior
Creatures you control with +1/+1 counters on them can't be blocked.
2 /
3
{1}{G}
Heroic Intervention
Instant
Permanents you control gain hexproof and indestructible until end of turn.
{X}{G}{G}
Hooded Hydra
Creature - Snake Hydra
Hooded Hydra enters the battlefield with X +1/+1 counters on it.
When Hooded Hydra dies, create a 1/1 green Snake creature token for each +1/+1 counter on it.
Morph {3}{G}{G}
As Hooded Hydra is turned face up, put five +1/+1 counters on it.
0 /
0
{X}{G}
Hungering Hydra
Creature - Hydra
Hungering Hydra enters the battlefield with X +1/+1 counters on it.
Hungering Hydra can't be blocked by more than one creature.
Whenever Hungering Hydra is dealt damage, put that many +1/+1 counters on it. (It must survive the damage to get the counters.)
0 /
0
{4}{G}{G}
Hydra Broodmaster
Creature - Hydra
{X}{X}{G}: Monstrosity X. (If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.)
When Hydra Broodmaster becomes monstrous, create X X/X green Hydra creature tokens.
7 /
7
{2}{G}
Hydra's Growth
Enchantment - Aura
Enchant creature
When Hydra's Growth enters the battlefield, put a +1/+1 counter on enchanted creature.
At the beginning of your upkeep, double the number of +1/+1 counters on enchanted creature.
{X}{G}{U}
Hydroid Krasis
Creature - Jellyfish Hydra Beast
When you cast this spell, you gain half X life and draw half X cards. Round down each time.
Flying, trample
Hydroid Krasis enters the battlefield with X +1/+1 counters on it.
0 /
0
{2}{G}
Inspiring Call
Instant
Draw a card for each creature you control with a +1/+1 counter on it. Those creatures gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Jungle Hollow
Land
Jungle Hollow enters the battlefield tapped.
When Jungle Hollow enters the battlefield, you gain 1 life.
{T}: Add {B} or {G}.
--
Karn's Bastion
Land
{T}: Add {C}.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
{2}{G}
Kodama's Reach
Sorcery - Arcane
Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.
--
Lair of the Hydra
Land
If you control two or more other lands, Lair of the Hydra enters the battlefield tapped.
{T}: Add {G}.
{X}{G}: Until end of turn, Lair of the Hydra becomes an X/X green Hydra creature. It's still a land. X can't be 0.
{X}{G}{G}{G}
Lifeblood Hydra
Creature - Hydra
Trample
Lifeblood Hydra enters the battlefield with X +1/+1 counters on it.
When Lifeblood Hydra dies, you gain life and draw cards equal to its power.
0 /
0
{2}{G}
Managorger Hydra
Creature - Hydra
Trample
Whenever a player casts a spell, put a +1/+1 counter on Managorger Hydra.
1 /
1
{X}{X}{U}{U}{U}{U}
Mass Manipulation
Sorcery
Gain control of X target creatures and/or planeswalkers.
{3}{G}
Migration Path
Sorcery
Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.
Cycling {2} ({2}, Discard this card: Draw a card.)
{X}{U}{U}
Mind Spring
Sorcery
Draw X cards.
{X}{G}
Mistcutter Hydra
Creature - Hydra
This spell can't be countered.
Haste, protection from blue
Mistcutter Hydra enters the battlefield with X +1/+1 counters on it.
0 /
0
--
Myriad Landscape
Land
Myriad Landscape enters the battlefield tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.
{X}{X}{G}{G}
Neverwinter Hydra
Creature - Hydra
As Neverwinter Hydra enters the battlefield, 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}.)
0 /
0
{X}{G}{G}
Nylea's Intervention
Sorcery
Choose one --
• Search your library for up to X land cards, reveal them, put them into your hand, then shuffle.
• Nylea's Intervention deals twice X damage to each creature with flying.
--
Opulent Palace
Land
Opulent Palace enters the battlefield tapped.
{T}: Add {B}, {G}, or {U}.
--
Path of Ancestry
Land
Path of Ancestry enters the battlefield tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{3}
Pristine Talisman
Artifact
{T}: Add {C}. You gain 1 life.
{X}{B}{B}
Profane Command
Sorcery
Choose two --
• Target player loses X life.
• Return target creature card with mana value X or less from your graveyard to the battlefield.
• Target creature gets -X/-X until end of turn.
• Up to X target creatures gain fear until end of turn. (They can't be blocked except by artifact creatures and/or black creatures.)
{1}{B}{G}
Putrefy
Instant
Destroy target artifact or creature. It can't be regenerated.
{1}{G}
Rampant Growth
Sorcery
Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
--
Reliquary Tower
Land
You have no maximum hand size.
{T}: Add {C}.
{G}{U}
Simic Ascendancy
Enchantment
{1}{G}{U}: Put a +1/+1 counter on target creature you control.
Whenever one or more +1/+1 counters are put on a creature you control, put that many growth counters on Simic Ascendancy.
At the beginning of your upkeep, if Simic Ascendancy has twenty or more growth counters on it, you win the game.
{1}
Sol Ring
Artifact
{T}: Add {C}{C}.
{X}{G}{G}
Steelbane Hydra
Creature - Turtle Hydra
Steelbane Hydra enters the battlefield with X +1/+1 counters on it.
{2}{G}, Remove a +1/+1 counter from Steelbane Hydra: Destroy target artifact or enchantment.
0 /
0
{X}
Stonecoil Serpent
Artifact Creature - Snake
Reach, trample, protection from multicolored
Stonecoil Serpent enters the battlefield with X +1/+1 counters on it.
0 /
0
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
{X}{U}
Syncopate
Instant
Counter target spell unless its controller pays {X}. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.
--
Temple of the False God
Land
{T}: Add {C}{C}. Activate only if you control five or more lands.
--
Thornwood Falls
Land
Thornwood Falls enters the battlefield tapped.
When Thornwood Falls enters the battlefield, you gain 1 life.
{T}: Add {G} or {U}.
{X}{B}{B}
Torment of Hailfire
Sorcery
Repeat the following process X times. Each opponent loses 3 life unless that player sacrifices a nonland permanent or discards a card.
{2}{G}
Unbound Flourishing
Enchantment
Whenever you cast a permanent spell with a mana cost that contains {X}, double the value of X.
Whenever you cast an instant or sorcery spell or activate an ability, if that spell's mana cost or that ability's activation cost contains {X}, copy that spell or ability. You may choose new targets for the copy.
{X}{G}{G}
Vastwood Hydra
Creature - Hydra
Vastwood Hydra enters the battlefield with X +1/+1 counters on it.
When Vastwood Hydra dies, you may distribute a number of +1/+1 counters equal to the number of +1/+1 counters on Vastwood Hydra among any number of creatures you control.
0 /
0
{X}{B}{G}{U}
Villainous Wealth
Sorcery
Target opponent exiles the top X cards of their library. You may cast any number of spells with mana value X or less from among them without paying their mana costs.
{X}{G}{G}
Voracious Hydra
Creature - Hydra
Trample
Voracious Hydra enters the battlefield with X +1/+1 counters on it.
When Voracious Hydra enters the battlefield, choose one --
• Double the number of +1/+1 counters on Voracious Hydra.
• Voracious Hydra fights target creature you don't control.
0 /
1
{B}{G}
Winding Constrictor
Creature - Snake
If one or more counters would be put on an artifact or creature you control, that many plus one of each of those kinds of counters are put on that permanent instead.
If you would get one or more counters, you get that many plus one of each of those kinds of counters instead.
2 /
3
{X}{G}
Wren's Run Hydra
Creature - Hydra
Reach
Wren's Run Hydra enters the battlefield with X +1/+1 counters on it.
Reinforce X--{X}{G}{G} ({X}{G}{G}, Discard this card: Put X +1/+1 counters on target creature.)
0 /
0
{1}{B}{G}{U}
Zaxara, the Exemplary
Legendary Creature - Nightmare Hydra
Deathtouch
{T}: Add two mana of any one color.
Whenever you cast a spell with {X} in its mana cost, create a 0/0 green Hydra creature token, then put X +1/+1 counters on it.
2 /
3
{5}{G}{G}
Zendikar Resurgent
Enchantment
Whenever you tap a land for mana, add one mana of any type that land produced. (The types of mana are white, blue, black, red, green, and colorless.)