Moka Icon Theme is a great icon theme designed and maintained by Moka Project. Moka Icon Theme was precisely designed for your Linux desktop. Moka supports any Linux distribution and desktop environment. So here I will try to install Moka Icon Theme on my Elementary OS Loki.
Since Moka icon theme is available through PPA, we can easily install Moka icon theme on Elementary OS via PPA. Open Terminal and paste these commands on Terminal:
sudo add-apt-repository ppa:moka/daily
sudo apt-get update
sudo apt-get install moka-icon-theme
Now open Settings and then click Tweaks. You may need to install Elementary Tweaks first.
Here are some screenshots of my Elementary OS Loki with Moka icon theme installed