Now a days it is bit hard to find perfect icon theme for your Linux desktop but there are some which can be considered as complete icon sets, I am not going to list all of them here instead we leave on you to find other icons from our 'Theme & Icons' page, if you are interested. Here comes two new themes called 'Just Colors' and 'Colors', uses various icons from other icon themes as well including: Vibrancy-Colors, Faenza and Numix icons themes. As its name shows off to you, there are many color variations in this theme (Blue, Green, Orange, Purple, Yellow and Default Version), you can choose which fits your GTK theme and desktop.
Since these icons are fairly new and in active development that means if you find any missing icon or encounter any problem with these icon sets then report it via linked page and hopefully it will be fixed as soon as possible for creator. You can use Unity Tweak Tool, Gnome-tweak-tool to change themes/icons.