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.

Serum Powder

{T}: Add {1} to your mana pool. Any time you could mulligan and Serum Powder is in your hand, you may remove your hand from the game, then draw that many cards. (You can do this in addition to taking mulligans.)

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.

Blinkmoth Nexus

{T}: Add {1} to your mana pool. {1}: Blinkmoth Nexus becomes a 1/1 Blinkmoth artifact creature with flying until end of turn. It's still a land. {1}, {T}: Target Blinkmoth creature gets +1/+1 until end of turn.

Simian Spirit Guide

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

Mutavault

{T}: Add {1} to your mana pool. {1}: Mutavault becomes a 2/2 creature with all creature types until end of turn. It's still a land.

Dismember

({B/P} can be paid with either {B} or 2 life.) Target creature gets -5/-5 until end of turn.

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.

Gemstone Caverns

If Gemstone Caverns is in your opening hand and you're not playing first, you may begin the game with Gemstone Caverns in play with a luck counter on it. If you do, remove a card in your hand from the game. {T}: Add {1} to your mana pool. If Gemstone Caverns has a luck counter on it, instead add one mana of any color to your mana pool.

Endless One

Ghost Quarter

Eldrazi Mimic

Matter Reshaper

Reality Smasher

Sea Gate Wreckage

Thought-Knot Seer

Warping Wail

Wastes

Eternal Scourge