Swamp

Tombstone, Career Criminal

When Tombstone enters, return target Villain card from your graveyard to your hand.
Villain spells you cast cost {1} less to cast.

Doctor Octopus, Master Planner

Other Villains you control get +2/+2.
Your maximum hand size is eight.
At the beginning of your end step, if you have fewer than eight cards in hand, draw cards equal to the difference.

Sandman's Quicksand

Mayhem {3}{B} (You may cast this card from your graveyard for {3}{B} if you discarded it this turn. Timing rules still apply.)
All creatures get -2/-2 until end of turn. If this spell's mayhem cost was paid, creatures your opponents control get -2/-2 until end of turn instead.

Morlun, Devourer of Spiders

Lifelink
Morlun enters with X +1/+1 counters on him.
When Morlun enters, he deals X damage to target opponent.

Island

Black Cat, Cunning Thief

When Black Cat enters, look at the top nine cards of target opponent's library, exile two of them face down, then put the rest on the bottom of their library in a random order. You may play the exiled cards for as long as they remain exiled. Mana of any type can be spent to cast spells this way.

The Spot's Portal

Put target creature on the bottom of its owner's library. You lose 2 life unless you control a Villain.

Prowler, Clawed Thief

Menace (This creature can't be blocked except by two or more creatures.)
Whenever another Villain you control enters, Prowler connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

Whoosh!

Kicker {1}{U} (You may pay an additional {1}{U} as you cast this spell.)
Return target nonland permanent to its owner's hand. If this spell was kicked, draw a card.

The Death of Gwen Stacy

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Destroy target creature.
II — Each player may discard a card. Each player who doesn't loses 3 life.
III — Exile any number of target players' graveyards.

Watery Grave

({T}: Add {U} or {B}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Fabled Passage

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then if you control four or more lands, untap that land.

Risky Research

Surveil 2, then draw two cards. You lose 2 life. (To surveil 2, look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Swarm, Being of Bees

Flash
Flying
Mayhem {B} (You may cast this card from your graveyard for {B} if you discarded it this turn. Timing rules still apply.)

Scorpion's Sting

Target creature gets -3/-3 until end of turn.

Flying Octobot

Flying
Whenever another Villain you control enters, put a +1/+1 counter on this creature. This ability triggers only once each turn.

Scorpion, Seething Striker

Deathtouch
At the beginning of your end step, if a creature died this turn, target creature you control connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on that creature.)

Sinister Hideout

This land enters tapped.
{T}: Add {U} or {B}.
{4}, {T}: Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Mysterio, Master of Illusion

When Mysterio enters, create a 3/3 blue Illusion Villain creature token for each nontoken Villain you control. Exile those tokens when Mysterio leaves the battlefield.