Corrupt

Corrupt deals damage to any target equal to the number of Swamps you control. You gain life equal to the damage dealt this way.

Waiting in the Weeds

Each player creates a 1/1 green Cat creature token for each untapped Forest they control.

Korlash, Heir to Blackblade

Korlash, Heir to Blackblade's power and toughness are each equal to the number of Swamps you control.
{1}{B}: Regenerate Korlash.
Grandeur — Discard another card named Korlash, Heir to Blackblade: Search your library for up to two Swamp cards, put them onto the battlefield tapped, then shuffle.

Wood Elves

When Wood Elves enters the battlefield, search your library for a Forest card, put that card onto the battlefield, then shuffle.

Defile

Target creature gets -1/-1 until end of turn for each Swamp you control.

Shadowspear

Equipped creature gets +1/+1 and has trample and lifelink.
{1}: Permanents your opponents control lose hexproof and indestructible until end of turn.
Equip {2}

Magus of the Coffers

{2}, {T}: Add {B} for each Swamp you control.

Yargle and Multani

Blanket of Night

Each land is a Swamp in addition to its other land types.

Lashwrithe

Living weapon (When this Equipment enters the battlefield, create a 0/0 black Phyrexian Germ creature token, then attach this to it.)
Equipped creature gets +1/+1 for each Swamp you control.
Equip {B/P}{B/P} ({B/P} can be paid with either {B} or 2 life.)

Vernal Bloom

Whenever a Forest is tapped for mana, its controller adds an additional {G}.

Woodland Cemetery

Woodland Cemetery enters the battlefield tapped unless you control a Swamp or a Forest.
{T}: Add {B} or {G}.

The Great Henge

This spell costs {X} less to cast, where X is the greatest power among creatures you control.
{T}: Add {G}{G}. You gain 2 life.
Whenever a nontoken creature enters the battlefield under your control, put a +1/+1 counter on it and draw a card.

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Dread Presence

Whenever a Swamp enters the battlefield under your control, choose one —
• You draw a card and you lose 1 life.
• Dread Presence deals 2 damage to any target and you gain 2 life.

Cabal Coffers

Farhaven Elf

When Farhaven Elf enters the battlefield, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

The Grand Evolution

(As this Saga enters and after your draw step, add a lore counter.)
I — Mill ten cards. Put up to two creature cards from among the milled cards onto the battlefield.
II — Distribute seven +1/+1 counters among any number of target creatures you control.
III — Until end of turn, creatures you control gain "{1}: This creature fights target creature you don't control." Exile The Grand Evolution, then return it to the battlefield (front face up).

Vorinclex

Trample, reach
When Vorinclex enters the battlefield, search your library for up to two Forest cards, reveal them, put them into your hand, then shuffle.
{6}{G}{G}: Exile Vorinclex, then return it to the battlefield transformed under its owner's control. Activate only as a sorcery.

Vorinclex // The Grand Evolution

Dakmor Sorceress

Dakmor Sorceress's power is equal to the number of Swamps you control.

Yavimaya, Cradle of Growth

Each land is a Forest in addition to its other land types.

Jarad, Golgari Lich Lord

Jarad, Golgari Lich Lord gets +1/+1 for each creature card in your graveyard.
{1}{B}{G}, Sacrifice another creature: Each opponent loses life equal to the sacrificed creature's power.
Sacrifice a Swamp and a Forest: Return Jarad from your graveyard to your hand.

Hag Hedge-Mage

When Hag Hedge-Mage enters the battlefield, if you control two or more Swamps, you may have target player discard a card.
When Hag Hedge-Mage enters the battlefield, if you control two or more Forests, you may put target card from your graveyard on top of your library.

Liliana of the Dark Realms

+1: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.
−3: Target creature gets +X/+X or -X/-X until end of turn, where X is the number of Swamps you control.
−6: You get an emblem with "Swamps you control have '{T}: Add {B}{B}{B}{B}.'"

Bubbling Muck

Until end of turn, whenever a player taps a Swamp for mana, that player adds an additional {B}.

Crypt Ghast

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Whenever you tap a Swamp for mana, add an additional {B}.