A Unity3d application made for Android VR (cardboard specifically) and Leap Motion.
As of 3/24/2017 there is no native solution for android vr and leap motion compatibility so as a work around visit https://github.com/levrn/gear-vr-leap-unity for this. The only disadvantage is having the leap motion usb tethered a computer. According to the discussion at https://community.leapmotion.com/t/vr-leap-on-cardboard-mobile-with-latest-v2-sdk/2625 leap motion already has an android leap motion sdk but you'll need to gain permission.