ubuntu 16.04 landscaping theme

Reference:
Unity plug-TWEAK-Tool

numix icon

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

Flatabulous theme

sudo add-apt-repository ppa:noobslab/themes
sudo apt-get update
sudo apt-get install flatabulous-theme

Each in his