Originally this list had only 5 Skins. But commenter Scott Wallace suggested Mimic Skin. I tried it and was blown away. Both my Fire TVs and my HTPC are now running Mimic Skin. Mimic combines the features of Aeon Nox and reFocus skins. In my tests, I found it to be very responsive and fluid. I did not hesitate to move it up to fourth on my list. Definitely worth a try even on low power devices such as Raspberry Pi.
Mimic skin is available to install through the Official Kodi skin downloads repository and can be installed easily from within Kodi settings.