Hextech Chest earning from getting an S- or higher in ARAM

I am an ARAM player, and I earn lots of chests by playing different champions, however, I wish there was a way to see, in champion select what champions I not yet have gotten a chest with. Either a small icon in the corner of the champion, or a hextech frame, also on champions I can trade with other players. Now I have to write down or memorize the champions I can earn a chest with. I don't know if this has been asked for before, but I notice now, late in the year, that I am needing this function to earn these chests faster.