GIT: https://github.com/bobgar/UnityVoxelEngine
I built this Unity voxel engine a few years ago, partly to take some of the lessons learned from building a similar engine in Javascript and improving upon them. Much more efficient use of polys, better culling and multi-threaded generation are a few of the improvements. I revisited the code recently to replacing my CPU-based generation with a Compute Shader approach.
I used this project for a few things over the years, most notably a workshop I did with high schoolers and a VR game where you ride a dragon around a voxel world, collecting food and fighting towers.
The master branch doesn’t actually do any interesting generation, it just sets up the voxel framework so its easy to set up a generator. A finished generator available on this branch and a screenshot of it is included below.