What are the specific classifications of traffic signs, which are just interesting?

There are many kinds of traffic signs, which can be divided into main signs and auxiliary signs. We just classify the main signs as:

(1) warning sign

(2) Prohibition signs

(3) Indicating signs

(4) Guiding signs

(5) signs of tourist areas

(6) Road construction safety signs

Auxiliary signs: auxiliary signs are signs set to protect traffic safety and smooth traffic when the main signs cannot fully express or indicate their contents. They are rectangles with black characters on a white background and black edges, which are attached to the main signs to help clarify the effect.