Daretti, Scrap Savant cant discard and Trash for Treasure on the same turn, but with Mishra actually discarding an artifact to reanimate with Darettis -2, Mishras effectively tapping for a mana
Unfortunately, Melmetal VMAX has seen better days, as it once sat closer to $11, but dropped below the plateau and hasn't seemed ready to break it again yet
Affinity only removes the colorless mana costs, so Witherbloom, the Balancer, at its cheapest, will still cost one green and one black mana
Id be tempted (heh) to get an alter done on Luminous Broodmoths artwork and call it The Eagles, the flying deus ex machina of Tolkiens tales
And like others have said, ARs /CHRs are huge bang for your buck for cool-but-cheap cards