Fairly cool rogue-like pixelish 3D RPG: http://www.delvergame.com/
Code and editor (but not the game assets) are now open-source (GPLv2):
https://github.com/Interrupt/delverengine
Editor seems quite cool and I think custom build and not part of the famework is is based on: https://libgdx.badlogicgames.com/
Would be cool if someone would make a mobile VR game out of it LibGDX seems to have the necessary parts in place: https://github.com/bernardjason/daydream