Blender - Blender is the open source, cross platform suite of tools for 3D creation.
Goxel - Goxel is a simple, but powerful voxel graphic editor with 24-bit color support, unlimited scene...
Sculptris - Sculptris: Enter a world of digital art without barriers.
MagicaVoxel - A free lightweight GPU-based voxel art editor and interactive path tracing renderer.
ShapeShop - ShapeShop is an advanced and professional 3D design and modeling application that comes with an easy-to-use and user-friendly interface.
Makers Empire 3D - Voxel editor made to be easy to use.