Suggested by Brian Dean, I compiled monsters that were in Super Sentai but not used for Power Rangers. I had compiled this list before back when in 2001 on my site when it was the Sentai Time Capsule but I had to remove it when we changed format. I do not know the real reason why any of these were used. Next I will be doing monsters that appeared on the show but only in background and got no closeup.
Dairanger / MMPR Season 2
Boss Kamikaze and Teacher Telephone
The gravestone was used for the Halloween episode but the three of these guys were the 3 idiots from Dairanger. They fought the Dairenoh (thunder megazord) twice but never died.
Bird Cage Vagabond
He had a vulture inside him and captured people and had a peg leg until he got his golden leg back. I guess he wasn't used because of time.
Zilong and Jiaxu
I used another picture of them but originally they were red and green. They are actually the armors of two human warriors. Probably not used because there wasn't enough footage of them in armor or too much fighting Dairanger.
Duke of Trumps
Appeared in the movie, his conglomerate form appeared in a picture book of MMPR, which always made me wondered why we never saw that monster. An insider told me Saban and Disney had to pay extra for the Movie footage so sometimes they didn't.
Kakuranger/MMPR season 3
Obvious why this one was not used, by her breasts.
Karakasa -- parts of it did get used for another monster
The Bratboy's first form.
Field commander who rules Machine Beasts with whip and has a human disguise and appeared in 3 episodes, probably not used because her outfit sort of looks like an S&M whipper. parts of it did get used for another monster
His footage mostly dealt with the Ohranger out of uniform, probably why not used. Also most of the footage was him as a ball.
Parts of him were used for Electrotramp for Power Rangers in Space/Ninja Turtle team-up episode "Shell Shocked."
Carranger / Turbo
Final was not used, Extra (above) was from the teamup with Ohranger.
Got the name Rockin' Roach.
Appeared in the Carranger vs. Ohranger teamup.
Megaranger / in Space
Neo Bat Nejire
Helmedor (Mega vs. Car)
Crab Nejilar (Mega vs. Car)
Gingaman / Lost Galaxy
Gaaragaara -- most likely not used because of the Hindu infulence, but according to Grnrngr.com, the costume might have appeared in the background.
Gregory (Ginga vs. Mega)
Jeeruda -- parts of it did get used for another monster
Boribar--parts of him was used for something else. His other form Pierre Bori was used for Quarganon.
Human Body Speciman Org
Charcoal Grill Org
New Year's Org
Rakushaasa (Gao vs. SS teamup)
Zeus Org (Movie)