Random things to leave in public places that could bring a stranger joy if they find them.

Miniature sculptures
Tiny mosaics
Yarn bombing
Small-scale murals
Miniature gardens
Fairy doors
Random/abstract patterns
Miniature light installations
Sticker art
Tiny collages
Urban mending
Chalk art
Street poetry
Marbles
Painted stones
Uplifting notes
Trinkets
Flowers
Handmade crafts
Seeds or plant starters
Coupons, gift certificates, or gift cards
Postcards
Bookmarks
Joyful sticky note art or phrases
A piece of poetry
A little bee bath
Tree gems / suncatchers
Shells
A button with a happy face on it
A pack of crayons