I don't think there are any 3d kivy games. It's not part of the core kivy api, so although we provide some examples of how to access the relevant opengl tools through the kivy api, there is not a lot of material about it. The main things available are a few projects from individual groups or people for 3d rendering tasks, but these have a range of specific purposes, are not games, and are mostly fairly limited in scope.
Of these, the main ones are nskrypnik's stuff on github (including the incomplete kivy3 framework which would aim to be a generic 3d interface), and the ddd (as in 3d) tools that tshirtman released yesterday, available in the kivy garden at
https://github.com/kivy-garden/garden.ddd .