Cavern of Souls

As Cavern of Souls enters the battlefield, choose a creature type. {T}: Add {1} to your mana pool. {T}: Add one mana of any color to your mana pool. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.

City of Traitors

If you play any land, sacrifice City of Traitors. {T}: Add two colorless mana to your mana pool.

Thorn of Amethyst

Noncreature spells cost {1} more to play.

Surgical Extraction

({B/P} can be paid with either {B} or 2 life.) Choose target card in a graveyard other than a basic land card. Search its owner's graveyard, hand, and library for any number of cards with the same name as that card and exile them. Then that player shuffles his or her library.

Simian Spirit Guide

Remove Simian Spirit Guide in your hand from the game: Add {R} to your mana pool.

Urborg, Tomb of Yawgmoth

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

Umezawa's Jitte

Whenever equipped creature deals combat damage, put two charge counters on Umezawa's Jitte. Remove a charge counter from Umezawa's Jitte: Choose one — Equipped creature gets +2/+2 until end of turn; or target creature gets -1/-1 until end of turn; or you gain 2 life. Equip {2}

Karakas

{T}: Add {W} to your mana pool. {T}: Return target legendary creature to its owner's hand.

Eldrazi Temple

{T}: Add {1} to your mana pool. {T}: Add {2} to your mana pool. Spend this mana only to cast colorless Eldrazi spells or activate abilities of colorless Eldrazi.

Ratchet Bomb

{T}: Put a charge counter on Ratchet Bomb. {T}, Sacrifice Ratchet Bomb: Destroy each nonland permanent with converted mana cost equal to the number of charge counters on Ratchet Bomb.

Endless One

Eldrazi Mimic

Endbringer

Matter Reshaper

Reality Smasher

Spatial Contortion

Thought-Knot Seer

Ancient Tomb

Eye of Ugin

Wasteland

Walking Ballista

Leyline of the Void

If Leyline of the Void is in your opening hand, you may begin the game with it on the battlefield. If a card would be put into an opponent's graveyard from anywhere, exile it instead.

Sorcerous Spyglass

As Sorcerous Spyglass enters the battlefield, look at an opponent's hand, then choose any card name. Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.