Energy Refractor

When Energy Refractor enters the battlefield, draw a card.
{2}: Add one mana of any color.

Sweltering Suns

Sweltering Suns deals 3 damage to each creature.
Cycling {3} ({3}, Discard this card: Draw a card.)

The Mightstone and Weakstone

When The Mightstone and Weakstone enters the battlefield, choose one —
• Draw two cards.
• Target creature gets -5/-5 until end of turn.
{T}: Add {C}{C}. This mana can't be spent to cast nonartifact spells.
(Melds with Urza, Lord Protector.)

Meria, Scholar of Antiquity

Tap an untapped nontoken artifact you control: Add {G}.
Tap two untapped nontoken artifacts you control: Exile the top card of your library. You may play it this turn.

The Deck of Many Things

{2}, {T}: Roll a d20 and subtract the number of cards in your hand. If the result is 0 or less, discard your hand.
1—9 | Return a card at random from your graveyard to your hand.
10—19 | Draw two cards.
20 | Put a creature card from any graveyard onto the battlefield under your control. When that creature dies, its owner loses the game.

Paradox Engine

Whenever you cast a spell, untap all nonland permanents you control.

Universal Solvent

{7}, {T}, Sacrifice Universal Solvent: Destroy target permanent.

Harnfel, Horn of Bounty

Discard a card: Exile the top two cards of your library. You may play those cards this turn.

Birgi, God of Storytelling

Whenever you cast a spell, add {R}. Until end of turn, you don't lose this mana as steps and phases end.
Creatures you control can boast twice during each of your turns rather than once.

Birgi, God of Storytelling // Harnfel, Horn of Bounty

Millstone

Elsewhere Flask

When Elsewhere Flask enters the battlefield, draw a card.
Sacrifice Elsewhere Flask: Choose a basic land type. Each land you control becomes that type until end of turn.

Thran Spider

Reach
When Thran Spider enters the battlefield, you and target opponent each create a tapped Powerstone token.
{7}: Look at the top four cards of your library. You may reveal an artifact card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Manifold Key

{1}, {T}: Untap another target artifact.
{3}, {T}: Target creature can't be blocked this turn.