Dragon of Mount Gulg (Ancient Copper Dragon) From a Commander or competitive standpoint, I can't quite figure out why this is as expensive as it is, it's sitting at $72.19 market
This combination of both print treatment and varied artwork will best maximize the visual effect to allow for your cards to pop, both on the battlefield and in a curated binder
This powerful card doesnt give you much time to find the answer, though
Ive heard some call it the green Shelly (Sheoldred, the Apocalypse) for formats like Standard and Modern and its not a perfect analog since Ouroboroid cant just solo people like Shelly can, and is worse against bolts but it does highlight something: letting this live for a turn or two can make life rough, even on its own
You'll normally be winning games through combat by playing high-power creatures
Cards with hexproof, shroud, indestructible, protection, and ward are notoriously difficult to remove from the battlefield