I'm a longtime enthusiast of voxel games and techniques, and Terracraft is the most recent in a long line of Voxel prototypes I've made. It supports the usual quasi-infinite world with persistent terrain editing, as well as an inventory and crafting system. I adhere to the base-game-is-a-mod philosophy; voxel types, items, and crafting recipes are all editable and extensible via simple JSON files.
Terracraft is on hold for awhile, but I'd love to revisit it and make an actual game out of it sometime.