You may want to check out Everquest Next. I think it would be fair to say that EQN is very close to a completely voxelized environment and at least mostly procedural. There is a great deal of curated content as well, but it seems like they are working on sourcing lots of that from players. The voxelized environment in EQN is based on Miguel Cepero's work. I believe they in fact hired him. I have been reading his blog for a long time and you can get a pretty good idea of the techniques that are being used.
A couple of quick hints to get you going in the right direction is that there are ( I believe ) a couple of generalized tricks involved to pull this off well. The first is using the 'correct' method to tesselate your voxel geometry. Minecraft literally uses cubes and you are familiar with the result. Another 'classic' method is the application of marching cubes/tetrahedra. This gives you fairly good organic-ish shapes but suffers from the inability to render sharp edges. Everything looks blobby. I believe the method used by EQN makes use dual-contouring, or a variant, which allows you to create organic shapes and also preserve sharp edges. A second factor is the ability to use different levels of resolution or scale for your voxels situationally. This allows you to craft human-scale things like cups and swords and whatnot, with human-scale details, and still craft houses and mountains and trees, without the need for storing extreme resolution in those items as well. It can be very tricky to patch together various bits of geometry tessellated from different voxel resolutions like this, and not end up with ugly visual artifacts. There is also the thorny issue of applying textures or materials to everything I have mentioned previously, which I have never investigated :)
http://procworld.blogspot.com/
A couple of quick hints to get you going in the right direction is that there are ( I believe ) a couple of generalized tricks involved to pull this off well. The first is using the 'correct' method to tesselate your voxel geometry. Minecraft literally uses cubes and you are familiar with the result. Another 'classic' method is the application of marching cubes/tetrahedra. This gives you fairly good organic-ish shapes but suffers from the inability to render sharp edges. Everything looks blobby. I believe the method used by EQN makes use dual-contouring, or a variant, which allows you to create organic shapes and also preserve sharp edges. A second factor is the ability to use different levels of resolution or scale for your voxels situationally. This allows you to craft human-scale things like cups and swords and whatnot, with human-scale details, and still craft houses and mountains and trees, without the need for storing extreme resolution in those items as well. It can be very tricky to patch together various bits of geometry tessellated from different voxel resolutions like this, and not end up with ugly visual artifacts. There is also the thorny issue of applying textures or materials to everything I have mentioned previously, which I have never investigated :)