I like the concept of rare cards here, but I dare say we have an unlimited source with the format (ie flash) that we're dealing with here. In a regular TCG, rares are something that are hard to come by, theoretically, and often give good benefits. They are sought after, and take a bit of effort or money to claim one as your own. Here, you can just more or less request a farm; that rare in that farm is near duplicated; both people have them. The only thing in this game that truly qualifies as a rare card are the old fire mark/pillars, and even then given enough time and probability, and they could propagate.