14 DAY TRIAL // Moka is a superb icon theme that works beautifully both in GNOME Shell and Unity and uses simple geometry and basic coloring. A new version has been released, bringing support for even more applications.
The Moka icon theme incorporates a quasi-flat style, using simple geometry and a few basic guidelines that make it compatible with almost all kinds of GNOME-based desktop environments, including Unity. The devs have made sure that it will work in a variety of systems, including Ubuntu, Fedora, OpenSuSE, and Arch Linux.
According to the developers, it's recommended that you add the repository to your system in order to get the latest updates as soon as possible. All you have to do is to enter these commands in a terminal (you will need to be root in order to make this work):
For Ubuntu (including 14.10)
sudo add-apt-repository ppa:moka/moka-icon-theme sudo apt-get update sudo apt-get install moka-icon-theme
For Fedora 20
sudo wget http://download.opensuse.org/repositories/home:/snwh:/moka-icon-theme/Fedora_20/home:snwh:moka-icon-theme.repo -O /etc/yum.repos.d/moka-icon-theme.repo sudo yum update sudo yum install moka-icon-theme
For openSUSE 13.1
sudo zypper addrepo -f http://download.opensuse.org/repositories/home:/snwh:/moka-icon-theme/openSUSE_13.1/ "Moka Icon Theme Repository" sudo zypper refresh sudo zypper install moka-icon-theme
The Arch Linux platform is a little special and you will need to install the moka-icons-git with Yaourt or Packer.
In order to activate the icon theme for your operating system, you will need a tool. For example, in Ubuntu you should use something like Ubuntu Tweak or Unity Tweak, but other operating systems will have their own software. Make sure that your operating system is supported before trying to install these packages.
Enjoy!