Emerald icon theme is based on Flattr and Breeze (Plasma icons) icons themes. It contains more than 4000+ icons for applications/folders/status/mime-types/others and it offers two themes: Emerald it can be used with light panels and Emerald-Dark use it if you are using dark theme.
It offers icons for light and dark panel support which means you can use these icons with any light or dark theme, and it contains more than 16,000+ icons. It is compatible with most of the Linux desktop environments such as Unity, Gnome, KDE, Cinnamon, Mate, Lxde, and others. For this icon theme most of the application icons available, still if you found any missing icon or bug in this set then report it. You can use Unity Tweak Tool, Gnome-tweak-tool to change themes/icons.
>>>Available for Ubuntu 16.10 Yakkety/16.04 Xenial/17.04/14.04 Trusty/12.04 Precise/Linux Mint 18/17/13/and other Ubuntu derivatives
To install Emerald-icon-theme in Ubuntu/Linux Mint open Terminal (Press Ctrl+Alt+T) and copy the following commands in the Terminal: