[Matrixbeast]

MMPR: Zach/Black Ranger (Always loved him. Always superior to fan favorite Billy and Tommy. However, I'll be fair and admit that I've had a soft spot for Tommy as the Green Ranger)
MMPR S2&3: Adam/Black Ranger (Come on. How can you not love Adam?)
Alien: Delphine/White Alien Ranger (I guess?)
Zeo: Jason/Zeo Gold (Jason was a cool dude, but he became so much cooler when he returned)
Turbo: TJ/Turbo Red (TJ is one of my favorite rangers of all time. People need to stop being so critical on Turbo after passing dumber bullshit for MMPR and Zeo)
In Space: Andros/Space Red (I love TJ in this series, too. But Andros was pretty cool)
Lost Galaxy: Kendrix/Galaxy Pink (How many rangers have been willing to make the ultimate sacrifice? Probably all, but only one proved to actually do it)
Lightspeed Rescue: Carter/Lightspeed Red (Always willing to pull the trigger)
Time Force: Tie between Jen/Time Force Pink and Eric/Quantum Ranger (Both were absolutely cool. Jen's story throughout the series made me love her, but Eric being the first "Brash" ranger made him more interesting than many of his predecessors)
Wild Force: Merrick/Lunar Wolf Ranger (He was kind of the only interesting one in the team)
Ninja Storm: Eh, none of them, really. I guess Cameron/Samurai Ranger
Dino Thunder: Trent/Dino White (I'm not really big on this series. They were all "Alright" at best. Trent was kind of interesting, though)
SPD: Bridge/SPD Green (I love a lot of the SPD Rangers. Jack, Skye, Z, and Doggie all had a good chance, but the amount of fun and energy Bridge brings is enough for me)
RPM: Ziggy/RPM Green (Gotta love the guy)

Can't comment on Mystic Force, Overdrive, and Jungle Fury since I don't remember them much. Only watched half of the Neo Saban era series.