Stickaholic
A Stickaholic is someone who is obsessed with stickers. It is like a workaholic or an alcoholic but with stickers instead of work or alcohol. They will collect stickers any chance they get. A Stickaholic probably has all the stickers in the world, or is planning to have them all someday.
Person 1: "Wow, look at all the stickers they have on their lockers!"
Person 2: "Yes, they are Stickaholics!"
Person 2: "Yes, they are Stickaholics!"