awesome-xfce

Make XFCE modern & beautiful

arc-dark theme

$ sudo apt-get install autoconf automake pkg-config libgtk-3-dev git
$ git clone https://github.com/horst3180/arc-theme --depth 1 && cd arc-theme
$ sudo ./autogen.sh --prefix=/usr
$ sudo make install

papirus icons

$ sudo add-apt-repository ppa:noobslab/icons
$ sudo apt-get update
$ sudo apt-get install papirus-icons

or numix-circle

$ sudo add-apt-repository ppa:numix/ppa
$ sudo apt-get update
$ sudo apt-get install numix-icon-theme-square