I would really love it if some form of trade-in existed for the buff cards. I currently have about 20-30 just sitting around that I don't use, mostly because I prefer the idle playstyle over clicking, so I don't ever use the dps=>click damage cards or the crit chance cards. It would be nice if we were able to redeem those for rubies at some fixed rate, so that they don't just sit in my stock acumalating