What is your suggestion?: Add a simple counter in CoX, ToA, ToB that shows you how many chests you've looted since you've seen a purple (either in your name or seen as a group). Should be togglable for people that don't want to see it.
Is this in OSRS?: I think there was a RL plugin for this on the main game but couldn't locate it?
Has this suggestion been accepted already?: No, not from my knowledge
How would this benefit Alora?: It would be nice to not have to keep track RL screenshots of when you last saw an item. With varying factors impacting drop rates (donor status, boosts, etc) it just either keeps you a little sane when going for the items or makes you tweak. All-in-all just a bit of fun, and with it being a toggle it would allow for players to choose to display it or not.