Yes only 12 episodes there will be a ova in january. There is also a spin-off called Dungeon ni Deai wo Motomeru no wa Machigatteiru Darou ka Gaiden: Sword Oratoria - 2017 and a movie that is not canonical Dungeon ni Deai wo Motomeru no wa Machigatteiru Darou ka Movie: Orion no Ya - 2019.
yea i did watch all of them but im sad that this season finished so fast and im sad that its rate its not higher