3D Monster Maze first 3d game on a home system
That depends entirely on how "3D" is defined.
For example, Star Ship for the Atari 2600 (1977) could also be considered "3D": https://www.youtube.com/watch?v=t2XmthOEEgo
Escape from the Mindmaster (Atari 2600, 1982) could be considered 3D too: https://www.youtube.com/watch?v=6Yf430Ls7Ew