Absolutely one of the best mob mods that I have found for Minetest. The models and textures are high quality, the sounds are immersive and the mob's AI is lifelike and believable. These weird little goblins are a total nuisance, in the best way possible. They swarm around in caves, mining, randomly gum up your tunnels with gross moss and sometimes steal torches right from in front of your nose while you're spelunking. As of the time of this review, FreeLikeGNU is still working on this mod and is receptive to feedback and suggestions, so there will probably be many more cool little features and different types of goblins to discover in future.
The ease of installing mods like this are the reason I switched to Minetest. You can really make the world you are playing in something totally unique. If you want a lively and immersive survival experience, you can't really go wrong with installing this mod.
In my Goblins works particular well with mobs that overhaul caves/underground spaces, like say df_caverns by Facedeer.