I am working on the new designer report that will be published in January 2020. Yay! 🎉 I will be sharing here some data along the way.
Feel free to ask questions if you want to know something specific.
To start with, I pulled the data for the number of icons sold in the 4 main styles during 2019 (from January 1, 2019 to November 30, 2019).
Outline is the most preferred style, closely followed by Glyph. In 3rd and 4th place come Flat and Filled Outline respectively.
All the other styles are far less popular (to get an idea of this, Badge style, which is the most popular from the bottom, usually sells around 1500 icons per month compared to Outline which sells around 25.000 icons per month on average). The grey line in the graph represents the sum of icons sold from all the other styles together.