Force of Will

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost.
Counter target spell.

Painter's Servant

As Painter's Servant enters, choose a color.
All cards that aren't on the battlefield, spells, and permanents are the chosen color in addition to their other colors.

Hydroblast

Choose one —
• Counter target spell if it's red.
• Destroy target permanent if it's red.

Plague Engineer

Deathtouch
As Plague Engineer enters, choose a creature type.
Creatures of the chosen type your opponents control get -1/-1.

Grafdigger's Cage

Creature cards in graveyards and libraries can't enter the battlefield.
Players can't cast spells from graveyards or libraries.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Underground Sea

Retrofitter Foundry

{3}: Untap Retrofitter Foundry.
{2}, {T}: Create a 1/1 colorless Servo artifact creature token.
{1}, {T}, Sacrifice a Servo: Create a 1/1 colorless Thopter artifact creature token with flying.
{T}, Sacrifice a Thopter: Create a 4/4 colorless Construct artifact creature token.

Thought Monitor

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Flying
When Thought Monitor enters, draw two cards.

Mox Opal

Metalcraft — {T}: Add one mana of any color. Activate only if you control three or more artifacts.

Urza's Saga

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Urza's Saga gains "{T}: Add {C}."
II — Urza's Saga gains "{2}, {T}: Create a 0/0 colorless Construct artifact creature token with 'This creature gets +1/+1 for each artifact you control.'"
III — Search your library for an artifact card with mana cost {0} or {1}, put it onto the battlefield, then shuffle.

Island

Ancient Tomb

{T}: Add {C}{C}. Ancient Tomb deals 2 damage to you.

Polluted Delta

{T}, Pay 1 life, Sacrifice Polluted Delta: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

Baleful Strix

Flying, deathtouch
When Baleful Strix enters, draw a card.

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Pithing Needle

As Pithing Needle enters, choose a card name.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.

Lotus Petal

{T}, Sacrifice Lotus Petal: Add one mana of any color.

Welding Jar

Sacrifice Welding Jar: Regenerate target artifact.

Thoughtseize

Target player reveals their hand. You choose a nonland card from it. That player discards that card. You lose 2 life.

Grindstone

{3}, {T}: Target player mills two cards. If two cards that share a color were milled this way, repeat this process.

Fatal Push

Destroy target creature if it has mana value 2 or less.
Revolt — Destroy that creature if it has mana value 4 or less instead if a permanent you controlled left the battlefield this turn.

Whir of Invention

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Search your library for an artifact card with mana value X or less, put it onto the battlefield, then shuffle.

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.