Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Static Prison

When this enchantment enters, exile target nonland permanent an opponent controls until this enchantment leaves the battlefield. You get {E}{E} (two energy counters).
At the beginning of your first main phase, sacrifice this enchantment unless you pay {E}.

Negate

Izzet Signet

Dovin's Veto

This spell can't be countered.
Counter target noncreature spell.

Guide of Souls

Whenever another creature you control enters, you gain 1 life and get {E} (an energy counter).
Whenever you attack, you may pay {E}{E}{E}. When you do, put two +1/+1 counters and a flying counter on target attacking creature. It becomes an Angel in addition to its other types.

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Azorius Signet

Galvanic Discharge

Choose target creature or planeswalker. You get {E}{E}{E} (three energy counters), then you may pay any amount of {E}. Galvanic Discharge deals that much damage to that permanent.

Boros Signet

Windfall

Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

Patron of the Arts

When this creature enters or dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Thirst for Discovery

Draw three cards. Then discard two cards unless you discard a basic land card.

Glimmer of Genius

Scry 2, then draw two cards. You get {E}{E} (two energy counters).

Aether Spike

Choose target spell. You get {E}{E} (two energy counters), then you may pay any amount of {E}. Counter that spell unless its controller pays {1} for each {E} paid this way.

Era of Innovation

Whenever an artifact or Artificer you control enters, you may pay {1}. If you do, you get {E}{E} (two energy counters).
Pay six {E}, Sacrifice this enchantment: Draw three cards.