Fortnite's update 11.30 turns out to be rather low in challenges to boost your Battle Pass. If we put aside the prestigious variants, the Stretch Goals challenges are quite poor, and you'll have to gain experience from elsewhere... It's a good thing because a real treasure trove of XP awaits you, hidden throughout the map.
These are small pieces of experience that are automatically collected. These are found everywhere and not only in notable places or major cities.
Each coin will give you 6250 XP points, and there are 64 coins to recover.