Dreamstone Hedronramp$0.19A colorless artifact mana rock that produces three mana and can be sacrificed for cards later. It fills a very similar role as a slower, higher-output ramp piece.
Worn Powerstoneramp$0.36Classic colorless ramp artifact that costs three and taps for two colorless mana, making it one of the closest functional equivalents. It accelerates into bigger spells just like Ur-Golem's Eye.
Thran Dynamoramp$3.60A very similar midgame artifact accelerator that taps for three colorless mana. It is one of the strongest direct upgrades to this effect.
Hedron Archiveramp$0.25Produces two colorless mana like Ur-Golem's Eye and later converts into card draw if needed. It is a strong functional match with added late-game utility.
Coalition Relicramp$0.33Colorless mana rock that can store charge counters and burst into extra mana later. It serves a similar ramp function while offering more flexibility.
Sisay's Ringramp$0.49A four-mana artifact that taps for two colorless mana, matching the core ramp profile closely. It is an older, straightforward equivalent.
Iron Myrramp$0.86A budget ramp option that produces one mana immediately through a creature body, but at a lower output than Ur-Golem's Eye. It fills the same acceleration slot in artifact-heavy decks.
Everflowing Chaliceramp$0.19Scales into a two-mana-producing artifact and is widely played as flexible colorless ramp. Kicked once or more, it overlaps strongly with Ur-Golem's Eye's role.