I have, couldn't find anything. Sorry about the vague nature, I'll try be more specific. So I grab a weapon and it does x damage with y,z modifiers and has ability A. Every time I use the weapon it gets its own version of experience points, but instead of simply leveling up the weapon from the experience, I can use the experience to increase 'x damage' to x+2" damage with "D,F,I" modifiers added onto it and it allows the use of "Q" spell. So rather than having players grinding for better weapons they stick with the one weapon and upgrade and customize it as they go along, creating emotional connection. (especially if there is a compelling lore and story behind the weapon)