These cards are mega-staples in the cEDH format, and both are fairly expensive to boot
(6/6/2025) Creatures that enter the battlefield attacking were never declared as attackers, so they won't count toward melee's effect
BPhillipYork: Duplicating artifacts is nice, though not massively impactful probably, but it will let you ramp up pretty aggressively and there are quite a few artifacts with decent ETB abilities that you can then turn around and sacrifice to generate even more ETBs, which is a fun way to play an artifact centric Grixis deck
Manufacturer: Wizards of the Coast Return to the Land of Light and Shadow Dare to enter the ever-changing plane of Lorwyn and Shadowmoor and discover your true self
There is a beloved two cost flashable for three that was pretty strongly played called Think Twice, this reduces a mana from it, but that's better in Spellslinger since you get two copies to trigger with Guttersnipe or self-mill since you can cast it later
The real standout is Aurora, Holding Court, the card taking over Amber decks and allowing some great Princess and Queen options in the early game to help build the Princess deck meta.