Ultra Q was the First TV Series produced by Tsuburaya Productions. This became the origin series for the long running Ultraman Series. But there was another TV Series which was in works before Ultra Q. This was WOO. Though Ultra Q started in 1966, the roots of it & Ultraman is related to WOO which was planned in 1963.
List of Incomplete Ultraman Films & Series: Real Ultraman for China, Sequel for Ultraman Great & more
There are many incomplete films that were planned during 80's & 90's when Ultraman was entertaining people through Manga, Anime and also overseas contents.
Interview: Hiroko Sakurai (Ultra Q & Ultraman's Heroine) → Reveals what they actually Thought of Ultra Series back then
Ultraman: Story of Light Exhibition was held at Fukushima's Cultural Center which displayed many things related to Ultra Series from Ultra Q to the current Ultraman Geed. Many Ultra Series Actors have appeared for Talk Show and many of the Ultra Series Episodes were screened. Ultra Q & Ultraman's Heroine → Hiroko Sakurai had also appeared. She had been interviewed.
Interviewer - What did you feel when you Tokusatsu Program - Ultra Q's Work came to you?
Hiroko Sakurai - Ultra Q is Beginning of Ultra Series. I joined as the Actress from Toho. Starting from Director Eiji Tsuburaya, Staff of Toho & Staff of TV Station (TBS) were giving a lot of efforts on this. I was deeply interested to see what will happen next.