Mazinger is a franchise created by Go Nagai, the first work in the series, Mazinger Z is notable because it was the first ever robot in fiction to be piloted from the inside whereas previously in Tetsujin 28-go was controlled remotely, as well as piloted mecha, Mazinger Z also invented calling out attacks and coining the term "Super Robot".
Original, Mazinger piloted by Kouji Kabuto
Sequel featuring new machine, Great Mazinger piloted by Tetsuya Tsurugi.
UFO Robot Grendizer
Series centred around alien Duke Fleed and the robot Grendizer, Kouji Kabuto returns as a supporting character.
Reboot OVA featuring Kouji Mabuto and Tetsuya Tsurugi the strongest incarnation; Mazinkaiser, the actually made its debut in Super Robot Wars.