Elemental War is our 3D tower defense made with the Unity engine. It was released as a Gothic II modification in 2010, but got so many improvements in the standalone version including a new game mode, that contains RPG and roguelite elements. Elemental War offers all in all three game modes, several maps and environments, quests, items and more.
Elemental War is for sale at Steam and itch.io.
If you want to read more about Elemental War, check out https://elemental-war.com.