Urza, Lord Protector | Legendary Creature | Human Artificer | Artifact, instant, and sorcery spells you cast cost {1} less to cast.
{7}: If you both own and control Urza, Lord Protector and an artifact named The Mightstone and Weakstone, exile them, then meld them into Urza, Planeswalker. Activate only as a sorcery. | Ryan Pancoast
3.5 LSV
Arcane Proxy | Artifact Creature | Wizard | Prototype {1}{U}{U} — 2/1 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.)
When Arcane Proxy enters the battlefield, if you cast it, exile target instant or sorcery card with mana value less than or equal to Arcane Proxy's power from your graveyard. Copy that card. You may cast the copy without paying its mana cost. | Kekai Kotaki
3.5 LSV
Surge Engine | Artifact Creature | Construct | Defender
{U}: Surge Engine loses defender and gains "This creature can't be blocked."
{2}{U}: Surge Engine becomes blue and has base power and toughness 5/4. Activate only if Surge Engine doesn't have defender.
{4}{U}{U}: Draw three cards. Activate only if Surge Engine is blue and only once. | Daarken
4.5 LSV
Bladecoil Serpent | Artifact Creature | Serpent | When Bladecoil Serpent enters the battlefield, for each {U}{U} spent to cast it, draw a card.
When Bladecoil Serpent enters the battlefield, for each {B}{B} spent to cast it, each opponent discards a card.
When Bladecoil Serpent enters the battlefield, for each {R}{R} spent to cast it, it gets +1/+0 and gains trample and haste until end of turn. | Joshua Cairos
4.5 LSV