Letter U for Uniform.
This uniform comes from my casual observations. Many artists do not wear a uniform, but plenty more do based on characters in movies and TV shows, real people interviewed on TV, and people at street art fairs.
Neck Scarf... this is the most popular one used. Summers can be difficult, but if the scarf is light weight, its possible to pull it off.
Striped Socks (or mismatched socks in bright colors)
Beret...Dated but some still use it
The bangles and paint brush are optional.