These are heroes that aren't technically Power Rangers, but still part of the team. This should be a more fun list. Click "read more" for my full article. (Debatably, a couple of them made their way onto the Black Rangers lists, but I considered those 2 rangers.)
#5: Captain Chaku (Beast Morphers)
#4: Ninjor (MMPR S3)
#3: Blue Senturion (Turbo)
Another cop from space, this one all robot. It is interesting that while Turbo was considered an underwhelming season, its extra rangers/allies are some of the most memorable. This robot cop comes to Earth from the future with an important warning about the great invasion that would happen during In Space. In between then and his arrival, he helps the Turbo Rangers in battle from time to time, gets turned evil twice, and even acts as a freelance police officer giving cars tickets. Good fun.
#2: Jarrod/Camille (Jungle Fury)
Talk about a power couple. (If only Power Rangers Disney allowed couples.) Maybe it is cheating to put both of them on one spot, but these two just go together. Jarrod is an interesting case about the arrogant bully who turns evil and Camille is the one that was already evil. But, amazingly, their stories don't stay one-dimensional like that. Jarrod gets a lot of backstory that showed he wasn't all bad and it becomes more of a tragedy has he is processed. Camille was never brainwashed, but turns good after a series of events and possibly due to her concern/feelings for Jarrod. It was a great story to follow.