Inspire Icons The Open Source icon set used in feren OS and designed exclusively to feren OS is now available to download officially and separate from the OS itself. This icon set is a warm mix of flat and non-flat icons working in harmony with each other and is now available for everyone to download today.
Source: Inspire Icons @ Gnomelook
GTK Theme used is called Vertex and can be seen here at Ubuntu Alive: Vertex Theme @ Ubuntu Alive
What is Feren Os? Follow the link below and check it out.