Three colors that aren't green can be hard to play with , so most of the artifacts are mana rocks that provide some colored mana
While not as talkative as their Brass Dragon brethren, Copper Dragons are very sociable and easygoing (unlike their Gold Dragon kin)
Between the use of fetch lands, instants and sorceries being cast, and creatures dying, a Tarmogoyf can grow quickly, becoming a noteworthy threat for only two mana
Incidentally, there are a number of discounted gold-bordered cards that don't show up on the Reserved List
Underdark Rift is a Land with dice roll synergy, as by paying , and exiling it, it let us roll a d10 at sorcery speed, to put target artifact, creature, or planeswalker into its owners library just beneath the top X cards of that library, where X is the result
The Passage taps with four to make any dork (even opposing ones for politics) unblockable for the turn