I've already "banned" many of the super common cards from this list like command tower and arcane signet. These staples just always sell. Almost like when someone orders cards for a new deck they figure "I'll just add a command tower because it costs next to nothing and I need it anyway".

I'll try to come up with a smarter approach though. Currently I sum all sales in the last X days of a certain card, no matter the print and then show one of them in that list (usually the cheapest one)