Posca is the paint marker brand of Uni (Mitsubishi's pencil company). It is at least known by every paint artists, designers and customization enthusiasts, and used on a lot of different surfaces and projects (from canvas to surf board, ceramic, textile, paper, glass, plastic, figurines, walls etc.)
It is loved by many and is often the default option: Posca almost means paint marker like Post-it means note.
This lack of competition can somewhat show in Posca's aging visual identity:
A New Posca
Using it. Some exemples