The Weatherseed Treaty

Read ahead (Choose a chapter and start with that many lore counters. Add one after your draw step. Skipped chapters don't trigger. Sacrifice after III.)
I — Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
II — Create a 1/1 green Saproling creature token.
III — Domain — Target creature you control gets +X/+X and gains trample until end of turn, where X is the number of basic land types among lands you control.

Zetalpa, Primal Dawn

Flying, double strike, vigilance, trample, indestructible

Jace, Architect of Thought

+1: Until your next turn, whenever a creature an opponent controls attacks, it gets -1/-0 until end of turn.
−2: Reveal the top three cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other on the bottom of your library in any order.
−8: For each player, search that player's library for a nonland card and exile it, then that player shuffles. You may cast those cards without paying their mana costs.

Thriving Heath

Thriving Heath enters tapped. As it enters, choose a color other than white.
{T}: Add {W} or one mana of the chosen color.

Vivid Creek

Vivid Creek enters tapped with two charge counters on it.
{T}: Add {U}.
{T}, Remove a charge counter from Vivid Creek: Add one mana of any color.

Fertile Footsteps

Search your library for a basic land card, put it onto the battlefield, then shuffle. (Then exile this card. You may cast the creature later from exile.)

Beanstalk Giant

Beanstalk Giant's power and toughness are each equal to the number of lands you control.

Beanstalk Giant // Fertile Footsteps

Network Terminal

{T}: Add one mana of any color.
{1}, {T}, Tap another untapped artifact you control: Draw a card, then discard a card.

Path to the Festival

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle. Then if there are three or more basic land types among lands you control, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Flashback {4}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Ornithopter of Paradise

Disdainful Stroke

Counter target spell with mana value 4 or greater.

Shimmerdrift Vale

Shimmerdrift Vale enters tapped.
As Shimmerdrift Vale enters, choose a color.
{T}: Add one mana of the chosen color.

Ashen Rider

Flying
When Ashen Rider enters or dies, exile target permanent.

Talisman of Curiosity

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

Darksteel Ingot

Indestructible (Effects that say "destroy" don't destroy this artifact.)
{T}: Add one mana of any color.

Search for Tomorrow

Search your library for a basic land card, put it onto the battlefield, then shuffle.
Suspend 2—{G} (Rather than cast this card from your hand, you may pay {G} and exile it with two time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)

Exotic Orchard

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

Bonder's Ornament

{T}: Add one mana of any color.
{4}, {T}: Each player who controls a permanent named Bonder's Ornament draws a card.

Ob Nixilis Reignited

+1: You draw a card and you lose 1 life.
−3: Destroy target creature.
−8: Target opponent gets an emblem with "Whenever a player draws a card, you lose 2 life."

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

Swamp

Island

Brokers Charm

Choose one —
• Target creature you control gets +1/+0 until end of turn. It deals damage equal to its power to target creature or planeswalker an opponent controls.
• Destroy target enchantment.
• Draw two cards.

Kaya, Intangible Slayer

Hexproof
+2: Each opponent loses 3 life and you gain 3 life.
0: You draw two cards. Then each opponent may scry 1.
−3: Exile target creature or enchantment. If it wasn't an Aura, create a token that's a copy of it, except it's a 1/1 white Spirit creature with flying in addition to its other types.

Maelstrom Colossus

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.)

Fumigate

Destroy all creatures. You gain 1 life for each creature destroyed this way.

Terastodon

When Terastodon enters, you may destroy up to three target noncreature permanents. For each permanent put into a graveyard this way, its controller creates a 3/3 green Elephant creature token.

Executioner's Capsule

{1}{B}, {T}, Sacrifice Executioner's Capsule: Destroy target nonblack creature.

Ulamog's Crusher

Annihilator 2 (Whenever this creature attacks, defending player sacrifices two permanents.)
Ulamog's Crusher attacks each combat if able.

Steel Hellkite

Flying
{2}: Steel Hellkite gets +1/+0 until end of turn.
{X}: Destroy each nonland permanent with mana value X whose controller was dealt combat damage by Steel Hellkite this turn. Activate only once each turn.

Market Festival

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional two mana in any combination of colors.

Seal of Cleansing

Sacrifice Seal of Cleansing: Destroy target artifact or enchantment.

Traveler's Amulet

{1}, Sacrifice Traveler's Amulet: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Biomantic Mastery

Draw a card for each creature target player controls, then draw a card for each creature another target player controls.

Vraska the Unseen

+1: Until your next turn, whenever a creature deals combat damage to Vraska the Unseen, destroy that creature.
−3: Destroy target nonland permanent.
−7: Create three 1/1 black Assassin creature tokens with "Whenever this creature deals combat damage to a player, that player loses the game."

Painful Truths

Converge — You draw X cards and you lose X life, where X is the number of colors of mana spent to cast this spell.

Talisman of Unity

{T}: Add {C}.
{T}: Add {G} or {W}. Talisman of Unity deals 1 damage to you.

Thriving Grove

Thriving Grove enters tapped. As it enters, choose a color other than green.
{T}: Add {G} or one mana of the chosen color.

Forest

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Omen of the Sea

Flash
When Omen of the Sea enters, scry 2, then draw a card.
{2}{U}, Sacrifice Omen of the Sea: Scry 2.

Plains

Seal of Primordium

Sacrifice Seal of Primordium: Destroy target artifact or enchantment.

Evolution Charm

Choose one —
• Search your library for a basic land card, reveal it, put it into your hand, then shuffle.
• Return target creature card from your graveyard to your hand.
• Target creature gains flying until end of turn.

Command Tower

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

Fertile Ground

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional one mana of any color.

Spelltwine

Exile target instant or sorcery card from your graveyard and target instant or sorcery card from an opponent's graveyard. Copy those cards. Cast the copies if able without paying their mana costs. Exile Spelltwine.

Martial Coup

Create X 1/1 white Soldier creature tokens. If X is 5 or more, destroy all other creatures.

Hostage Taker

When Hostage Taker enters, exile another target creature or artifact until Hostage Taker leaves the battlefield. You may cast that card for as long as it remains exiled, and mana of any type can be spent to cast that spell.

Have

Hornet Queen

Flying, deathtouch
When Hornet Queen enters, create four 1/1 green Insect creature tokens with flying and deathtouch.

Urban Evolution

Draw three cards. You may play an additional land this turn.

Geode Golem

Trample
Whenever Geode Golem deals combat damage to a player, you may cast your commander from the command zone without paying its mana cost. (You still pay any additional costs.)

Bring to Light

Converge — Search your library for a creature, instant, or sorcery card with mana value less than or equal to the number of colors of mana spent to cast this spell, exile that card, then shuffle. You may cast that card without paying its mana cost.

Finality

You may put two +1/+1 counters on a creature you control. Then all creatures get -4/-4 until end of turn.

Find

Return up to two target creature cards from your graveyard to your hand.

Find // Finality

Sandwurm Convergence

Creatures with flying can't attack you or planeswalkers you control.
At the beginning of your end step, create a 5/5 green Wurm creature token.

Mortify

Negate

Uncharted Haven

Uncharted Haven enters tapped. As it enters, choose a color.
{T}: Add one mana of the chosen color.

Vivid Grove

Vivid Grove enters tapped with two charge counters on it.
{T}: Add {G}.
{T}, Remove a charge counter from Vivid Grove: Add one mana of any color.

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Saheeli's Artistry

Choose one or both —
• Create a token that's a copy of target artifact.
• Create a token that's a copy of target creature, except it's an artifact in addition to its other types.

Eureka Moment

Draw two cards. You may put a land card from your hand onto the battlefield.

Arcane Signet

Harrow

As an additional cost to cast this spell, sacrifice a land.
Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.

Dakkon, Shadow Slayer

Dakkon, Shadow Slayer enters with a number of loyalty counters on him equal to the number of lands you control.
+1: Surveil 2.
−3: Exile target creature.
−6: You may put an artifact card from your hand or graveyard onto the battlefield.

Thriving Isle

Thriving Isle enters tapped. As it enters, choose a color other than blue.
{T}: Add {U} or one mana of the chosen color.

Diluvian Primordial

Flying
When Diluvian Primordial enters, for each opponent, you may cast up to one target instant or sorcery card from that player's graveyard without paying its mana cost. If a spell cast this way would be put into a graveyard, exile it instead.

Myr Battlesphere

When Myr Battlesphere enters, create four 1/1 colorless Myr artifact creature tokens.
Whenever Myr Battlesphere attacks, you may tap X untapped Myr you control. If you do, Myr Battlesphere gets +X/+0 until end of turn and deals X damage to the player or planeswalker it's attacking.

Abuelo, Ancestral Echo

Flying, ward {2}
{1}{W}{U}: Exile another target creature or artifact you control. Return it to the battlefield under its owner's control at the beginning of the next end step.

Atraxa, Grand Unifier

Flying, vigilance, deathtouch, lifelink
When Atraxa, Grand Unifier enters, reveal the top ten cards of your library. For each card type, you may put a card of that type from among the revealed cards into your hand. Put the rest on the bottom of your library in a random order. (Artifact, battle, creature, enchantment, instant, land, planeswalker, and sorcery are card types.)

Woodcaller Automaton

Prototype {2}{G}{G} — 3/3 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.)
When Woodcaller Automaton enters, if you cast it, untap target land you control. It becomes a Treefolk creature with haste and base power and toughness equal to Woodcaller Automaton's power and toughness. It's still a land.

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Rampaging Baloths

Trample
Landfall — Whenever a land you control enters, you may create a 4/4 green Beast creature token.

Jungle Hollow

Jungle Hollow enters tapped.
When Jungle Hollow enters, you gain 1 life.
{T}: Add {B} or {G}.

Putrefy

Destroy target artifact or creature. It can't be regenerated.

Evolving Wilds

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Storm Herd

Create X 1/1 white Pegasus creature tokens with flying, where X is your life total.

Ash Barrens

{T}: Add {C}.
Basic landcycling {1} ({1}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Vivid Meadow

Vivid Meadow enters tapped with two charge counters on it.
{T}: Add {W}.
{T}, Remove a charge counter from Vivid Meadow: Add one mana of any color.

Omen of the Hunt

Flash
When Omen of the Hunt enters, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
{2}{G}, Sacrifice Omen of the Hunt: Scry 2.