Colored-plastic icon set is designed by same developer of Apple-art and Hi-lights icons. This icon set is colorful, well designed and looks good with all kind of light and dark themes. Unfortunately developer stopped working on this set but it is still complete icon set and works with all kind of Linux versions. Also check icons collection. You can use Unity Tweak Tool, Gnome-tweak-tool or Ubuntu-Tweak to change icons.
To install Colored-Plastic icons on Ubuntu/Mint open Terminal (Press Ctrl+Alt+T) and copy the following commands in the Terminal:
To install Colored-Plastic icons in Previous Ubuntu/Linux Mint version open Terminal (Press Ctrl+Alt+T) and copy the following commands in the Terminal:
Source: Colored Plastic