I made a minecraft-y voxel world in WebGL2 a while back... just realised it's not on the blog. Now it is!
I'll hopefully write this up a bit more soon - because I want to remember how I did the chunk generation! The basic architecture was inspired from this excellent (and massive!) WebGL series by SketchPunkLabs.
The voxel world also served as a base for my spooooky simultaneous 2D/3D game: Obaké.