When it comes to the Power Rangers series, the specialty Rangers and the Red Rangers tend to get a lot of the spotlight. That's due in large part to the special Rangers - the Sixth Rangers, or late additions to the team - having more advanced power sets than the rest of the team. That's also due to most Red Rangers being the team leaders who need to learn a lesson throughout their series.
Some Power Rangers just don't get as much time in the spotlight as others. Not every Power Ranger can be Tommy Oliver, after all, heading up three different Ranger teams, mentoring another, and appearing in even more crossover episodes. That doesn't mean they aren't just as important. These particular Power Rangers are often overlooked, but make huge contributions to their teams.
RJ (Jungle Fury)
The first Purple Ranger of the franchise, RJ appears to be a pretty laid-back guy. He might run his own business, but he always seems to have room for fun. He's also more of a mentor than a Power Ranger initially.
Though RJ has a wolf spirit (and an unbreakable bond with one at that), he spends a lot of time imparting advice to the main team of Rangers, joining them in the fight when they need help. His advice comes in handy since he's a master of many different fighting styles, and knows exactly who to approach when he's not the one with the advice they need.
Kira (Dino Thunder)
With a voice like an angel, Kira becomes a professional singer in the future that Power Rangers: SPD exists in. As a Power Ranger though, Kira's scream packs a big punch.
Her particular power gives her an edge against some of the villains created by Mesogog, but she's underrated not because of her performance in her own series, but her performance in others. She has the distinction of appearing in two different crossovers - rare for any Power Ranger who isn't from the Mighty Morphin Power Rangers series. Kira helped both the Operation Overdrive and SPD teams on difficult missions.
Emma (Megaforce)
For some fans, the Power Rangers Megaforce season was a bit of a letdown. Though the Rangers on the team could access the abilities of all of the Rangers that came before them, not all fans enjoyed that the main team appeared to be inspired by previous Rangers as well.
Emma in particular had a lot in common with the Pink Rangers who came before her. She sings, has a fondness for animals, and is unfailingly kind. Some fans might mistake that kindness for weakness. Emma's kindness, however, informs the way she fights. She wants everyone to have a chance at their best life and wants to give everyone the benefit of the doubt. That's why she works so hard for her team.
TJ (Turbo, In Space)
Unlike most of the other Rangers here, TJ is a Red Ranger - for a little while. He steps into some pretty big shoes when he takes over as the team leader in Power Rangers Turbo. TJ does his absolute best to make sure his team survives, even as it seems like their world is coming to an end. He makes the decision with his friends to go to space to find a missing Zordon even.
Of course, TJ also steps down as team leader when the group gets to space. Andros takes over, giving the group new morphers when their old ones were useless. TJ takes a step back since he's no longer the person calling all the shots, but he never lets his teammates down.
Bridge (SPD)
Power Rangers SPD is very different from the other series in the franchise. For one, the Rangers are a law enforcement group instead of secret superheroes. For another, the colors denote their rank on the team.
Bridge works his way up from Green to Blue Ranger over the course of the series, proving himself to his team with his skills of analysis. Following the end of the series, he becomes the team's Red Ranger and appears in the Operation Overdrive crossover with Kira, giving a hand to another team.
Xander (Mystic Force)
Xander might win the Power Ranger award for most growth in the franchise - though not when he's literally growing into a tree. When he first begins his journey as a Ranger, Xander believes he can be charming enough to evade any consequences. That's definitely not true, and it gets him into trouble plenty of times.
He eventually learns to accept when he makes mistakes and to own up to the wrongs he's made instead of trying to cover them up. Like Bridge, he journeys to help fellow rangers in the same crossover episode, but he also finds growth in his civilian life, becoming the manager of the store where he works.
Alyssa (Wild Force)
Alyssa is something of a renaissance woman, and she doesn't get nearly enough credit for all the things she can do in Power Rangers Wild Force. Like Emma, she's a gentle soul. She often acts as the mediator when teammates don't see eye-to-eye. That's not all though.
Her fighting skills aren't just the result of becoming a Power Ranger. Her father trained her in a variety of martial arts before she becomes the White Ranger. She also manages to bond with three different zords while on the team, and she acts as their medic.
Cassie (Turbo, In Space)
When Cassie becomes the Pink Ranger, she breaks the mold. She's edgier than Kimberly and Kat, the two young women who come before her. Cassie is more of a rebel than they are, though she still has their soft spot for animals.
Cassie takes over for Kat in Power Rangers Turbo after helping to save people in a crisis. She also, like TJ, makes the decision to go to space with the rest of the team to look for Zordon. Beyond that, she even teams up with the Power Rangers: Lost Galaxy members in an effort to fight the Psycho Pink Ranger. She loses that fight, but she desperately tries to help them anyway.
Adam (Mighty Morphin, Zeo, Turbo)
Of the underrated Rangers, Adam is the most decorated. Like Cassie and TJ in later seasons, he's chosen to replace an existing Ranger because he demonstrates a commitment to helping people in Mighty Morphin Power Rangers. Adam is initially quiet and reserved, content to observe and lend a hand, but he breaks out of his shell in Power Rangers Zeo.
Adam goes from being the quiet guy at the back to Tommy's second-in-command of the team. He continues to learn new martial arts skills, even when he's already on his third round of being a Ranger. Adam also returns to mentor his own replacement in a handful of episodes and shows up for a few crossovers of his own. He never stops being a Power Ranger that other Rangers can turn to for help.
Tanya (Zeo, Turbo)
Tanya joins the Zeo team just as they are formed, bringing one part of the Zeo crystal to the group in place of a leaving Ranger. After spending her formative years in a small village, she not only has to adapt to being a superhero but also to living in a major city with a completely new social structure.
Tanya adapts spectacularly. She also sings, dances, and plays just about any sport she attempts. It's amazing that she finds the time to do it all and remain a Ranger on two different teams. She's a fan favorite who doesn't always get the recognition she deserves for her abilities. As a teenager, she even unravels the clues to find her missing parents.