As per our chat on discord, it would be nice to have the ability to have groupings of items with a rarity that would then stop duplicates from being added in.

Example: 

Assault Rifle - Blue - 10% chance

Assault Rifle - Red - 30% chance

Assault Rifle - green - 50% chance

Then rolls the Assault rifle and subsequently rolls which colour based off the 'rarity' to avoid spawning all 3.