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.

Trinisphere

As long as Trinisphere is untapped, each spell that would cost less than three mana to cast costs three mana to cast. (Additional mana in the cost may be paid with any color of mana or colorless mana. For example, a spell that would cost {1}{B} to cast costs {2}{B} to cast instead.)

Magus of the Moon

Nonbasic lands are Mountains.

Goblin Rabblemaster

Other Goblin creatures you control attack each turn if able. At the beginning of combat on your turn, put a 1/1 red Goblin creature token with haste onto the battlefield. Whenever Goblin Rabblemaster attacks, it gets +1/+0 until end of turn for each other attacking Goblin.

Chalice of the Void

Chalice of the Void enters the battlefield with X charge counters on it. Whenever a player casts a spell with converted mana cost equal to the number of charge counters on Chalice of the Void, counter that spell.

Kiki-Jiki, Mirror Breaker

Haste {T}: Put a token that's a copy of target nonlegendary creature you control onto the battlefield. That token has haste. Sacrifice it at the beginning of the next end step.

Moggcatcher

{3}, {T}: Search your library for a Goblin card and put that card into play. Then shuffle your library.

Simian Spirit Guide

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

Stingscourger

Echo {3}{R} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.) When Stingscourger comes into play, return target creature an opponent controls to its owner's hand.

Chrome Mox

Imprint — When Chrome Mox enters the battlefield, you may exile a nonartifact, nonland card from your hand. {T}: Add one mana of any of the exiled card's colors to your mana pool.

Murderous Redcap

When Murderous Redcap comes into play, it deals damage equal to its power to target creature or player. Persist (When this creature is put into a graveyard from play, if it had no -1/-1 counters on it, return it to play under its owner's control with a -1/-1 counter on it.)

Krenko, Mob Boss

{T}: Put X 1/1 red Goblin creature tokens onto the battlefield, where X is the number of Goblins you control.

Goblin Settler

When Goblin Settler comes into play, destroy target land.

Siege-Gang Commander

When Siege-Gang Commander comes into play, put three 1/1 red Goblin creature tokens into play. {1}{R}, Sacrifice a Goblin: Siege-Gang Commander deals 2 damage to target creature or player.

Blood Moon

All non-basic lands are now basic mountains.

Sudden Shock

Split second (As long as this spell is on the stack, players can't play spells or activated abilities that aren't mana abilities.) Sudden Shock deals 2 damage to target creature or player.

Tuktuk Scrapper

Whenever Tuktuk Scrapper or another Ally enters the battlefield under your control, you may destroy target artifact. If that artifact is put into a graveyard this way, Tuktuk Scrapper deals damage to that artifact's controller equal to the number of Allies you control.

Ancient Tomb

Mountain

({T}: Add {R}.)