MineClone2 is pretty much as close as you can get to Minecraft without playing Minecraft. It's free, open source and runs on the Minetest voxel game engine. A new release is now available with version 0.81.0.
I doubt it will need much of an introduction for people new to it: a sandbox game where you go and do whatever you want. The new release requires either 5.5.1 or 5.6.0 at a minimum.
Some of the main highlights from the new version include:
- A rewrite of signs, including coloured text.
- Villager schedule implemented, villager fixes.
- Nether terrain generation improved for a lot more open space.
- Nether bulwark (mini-bastion) added.
- Nether bridge fragment.
- Strider mob added.
- Raids added.
- Axolotl mob added.
- Beehives and honey added.
- Ocean temples added.
- Lots more including various AI improvements.
Minetest has quite a lot of mods, and a few big game packs like this. If you've not tried Minetest or MineClone2 for a while, it looks like a good time to jump back in.