How to mark weapons of different rarities in Fortnite?
Know that to complete this challenge, the most complicated task will be to get your hands on weapons of different rarities. The rarity of a weapon is recognized by its color: Orange → Legendary, Pink → Epic, Blue → Rare, Green → Atypical and Gray → Common.Therefore, to validate the challenge, you will have to mark multiple weapons with different colors. To do this, when you're facing a weapon, aim it, but instead of picking it up, press the mouse wheel if you're on PC. This will tell your teammates about the weapon, its rarity, and its location, which can be quite useful.
Be careful though, if you have modified the marking key, you will have to use the one you have chosen. If you can't remember, check in the settings (Control → Communication → "Place Mark").
Now that you know how to do it, you should be able to complete this challenge in a single game.