Gordon McLeod has created 10 new themes which are all part of his Planet series. Mercury was the first but now available are Earth, Luna, Mars, Venus, Jupiter, Pluto, Saturn, Uranus and Neptune. Check them all out here: https://moodle.org/plugins/browse.php?list=contributor&id=1039666.
The Planet series are all based on the core theme Binarius and feature a common Moodle user information footer, each color scheme is inspired by the namesake planet/satellite. All can be downloaded from the plugin repository today: https://moodle.org/plugins/search.php?s=planet