Faenza Icon Theme for FX File Explorer: a complete set of high-definition icons for FX+.  
YOU MUST HAVE FX FILE EXPLORER 3.1 (or later) *AND* FX PLUS INSTALLED TO USE ICON THEMES.  Themes will also work with the FX Plus free 7-day trial.
Download FX here: https://play.google.com/store/apps/details?id=nextapp.fx
This app will NOT add an icon to your launcher: to use this theme, open FX, tap the view menu (second from the right), tap "Theme".  Select the "Icon Set" tab and then choose a "Faenza" option.  To uninstall an FX theme, either use FX's "add-ons" option from the home screen, or visit the Settings of your device and then the "Applications" section.
The Faenza icon theme for FX+ is distributed under the GNU General Public License.  (Please note: this license only applies to this icon theme package).  Source including SVG icons is available here: http://android.nextapp.com/fx/theme/faenza/r1/FX-Theme-Faenza_src_r1.tgz  You can use this source to build derivative themes, or as an example of how to create your own custom themes for FX+.