I spent part of the past summer playing with synthetic felt- acrylic, I think. If the felt is heated with a heat gun, it melts unevenly and creates very interesting holes and shapes. if there has been stitching done on the surface before melting, the thread ( cotton or rayon ) resists the burning and leaves delicious patterns . I shall pursue this further and WILL get better photos of the finished products!
I have also played with Tyvek, Evolon, Lutraur and have had a blast!