Re: Antistatic mouse mats are still a thing to this day
A lot of the blended fabrics with a high man made content or those made of man made fabrics, such as rayon, will generate a large static charge.
Think of the amber rod rubbed by a cloth in a basic science demonstration.
Have personally worked in conditions where 100% natural materials were a requirement for all clothing worn while working. This is over and above the usual grounding strap precautions.