Butt Monkey: Rocky has the absolute worst luck. Throughout the series all manner of unfortunate things happen to him, starting with being demoted down to blue ranger, getting unfairly blamed for problems, nearly being turned into a plant by a monster created from a plant he'd accidentally created. It eventually reaches its apex in the transition between Zeo and Turbo when he's hospitalised.
Heroic BSOD: Went through one in "Mondo's Last Stand" when he was convinced that Jason was replacing him.
Evil Is Hammy: In "King for a Day", Prince Gasket brainwashed Tommy into thinking he was their king and that the other Power Rangers were his enemies. He then proceed to act just as hammy as he did when he was the evil Green Ranger.
Evil Laugh: Got it back when he was brainwashed in "King for a Day".
Law of Chromatic Superiority: As the Red Ranger, Tommy is in charge, gets his own individual Zord, and is usually the one to use the Battle Wield.
Trey of Triforia / Gold Ranger I | (Actors: Tom, Tim and Ted DiFilippo)
Cast from Hit Points: The Gold Ranger powers are tied in to Jason's life-force, and so the Machine Empire do their best to wear him down, which causes his powers to start fritzing by the end of the series. It gets bad enough that Jason nearly dies.
Real Life Writes the Plot: David Yost reportedly didn't like the slurs against his homosexuality on the set and walked off before the writers could make up a story to write him out.
Rapid Aging: Apparently the explosion messed with his molcule more then he thought as they aged him into an old man. Forcing him to have to go with the Aquaians homeworld to restore his youth. He winds up staying there when he falls in love with one of the female scientists and that is the last we see of him until Power Rangers Megaforce. Albeit as a Fake Shemp.
Red Herring: Was suspected by Rocky and the fans to be the Gold Ranger. Tried to be said Ranger - but particles his body received from the Command Center's explosion rejected the power.
Chuck Cunningham Syndrome: He was last seen in "Rangers of Two Worlds, Part 2" unsuccessfully facing the monsters controlling the Megazords. Unlike with Ninjor, the show didn't provide even the slimmest explanation of where he went afterwards.
Ernie | (Actor: Richard Genelle)
Ascended Extra: After three years of being a recurring character, Ernie was promoted to main cast for Zeo.
Bulk & Skull | (Actors: Paul Schrier and Jason Narvy)
Badass Normal: In "King for a Day, Part 2," they fended off Cogs, the mooks that Rangers preferred to fight while morphed.
Ascended Extra: As with Ernie, Stone was promoted to main cast after being a recurring character.
Bad Boss —> Benevolent Boss: Played both ways. He's prone to yelling and punishment, but of course, he's the boss of Bulk and Skull. Given their antics, anyone else would've fired them immediately, but Stone obviously has a soft spot for them.
Badass Normal: In "Graduation Blues," he stumbled upon Goldar and Rito - thinking an invasion was a foot. He chased them all over the park to try to arrest them. Granted, the two were amnesic and not up to no good, but Stone didn't know that.
Hidden Depths: Stone turns out to have enough knowledge on coffee to write an entire book on the subject.
Happily Married: To Queen Machina. The two spend a lot of their screen-time complimenting each other, or exchanging cutesy nicknames with one another.
Motive Decay: When the Machine Empire first attacked Earth, it's because "our solar system is the final link in a chain of galaxies already conquered" by them. Conquering Earth would effectively give them control of the universe (or at least enough of it to prevent any opposition). The Zeo Rangers were initially viewed as an "interesting diversion" to make the conquest more entertaining. By the end of the season, though, Mondo is more interested in defeating the Rangers. Possibly justified in that the Rangers repeatedly defeated him (including briefly destroying him), making it personal.
Orcus on His Throne: Like any other Ranger Big Bad, he directs monsters against the Rangers. The trope is subverted, though, when he does fight the Rangers in "Mondo's Last Stand" and "Good as Gold." They wind up having no more trouble beating him than the average monster.
Spared by the Adaptation: His Ohranger counterpart didn't get rebuilt. Although his fate does catch up with him in In Space.
Oh, No... Not Again!: Her reaction to Mondo being blown up. Sprocket understandably questions this, causing her to reveal Mondo was just rebuilt.
Orcus on His Throne: Despite being co-head of the Machine Empire, Machina never gets involved in a fight, and barely ever creates or even hires a monster. When Louie Kaboom takes over, she makes no direct effort to fight him.
Parental Favouritism: Between Gasket and Sprocket, when the two are together, she prefers Gasket, snubbing Sprocket as "the baby" right to his face.
So Proud of You: Only not because of some accomplishment, but because Gasket and Sprocket are bickering with one another.
Bratty Half-Pint: He's a litte kid, after all. Most of his brattiness is directed at Clank.
Decomposite Character: The two bodies of Prince Buldont from Ohranger become two separate characters with Buldont's Prince for going to Prince Sprocket.
Genre Savvy: Sprocket actually figures out that growing to giant size and fighting a Zord is a death sentence for a Power Rangers villain, and manages to trick Gasket and Archerina into doing exactly that in an attempt to kill them. And it very nearly works.
Off with His Head!: Rita and Zedd's bomb blows Sprocket's head clean off (with his decapitated head being in full view when last seen).
Klank & Orbus | (Voice actors: Oliver Page and Barbara Goodson)
Catch Phrase: Klank tends to say "Around and around and away we / ye go!" when tossing Orbus at a monster.
Deadpan Snarker: Orbus gets a number of digs in, usually at Klank's expense. Also when making a monster grow, Orbus usually makes a quip somehow related to their powers.
Make My Monster Grow: Klank throws Orbus at the fallen body of the monster of the day, making it grow.
Klank: This is my favorite part of our battles, Orbus.
Orbus: Sure, I do all the work.
Scotland: Klank is Scottish. There's no specific reason for this, but it does make him a fairly memorable minion.
Big Bad Wannabe: He sought to become leader of the Machine Empire in King Mondo's absence, but failed to achieve any serious victories that would allow that ascension. Plus, he beat a hasty retreat after Mondo came back.
Cain and Abel: With his little brother, Sprocket. Gasket openly declares his intentions to take Sprocket to pieces to his face, but Sprocket ultimately wins out by nearly tricking his brother into getting killed by the Rangers.
Decomposite Character: The two bodies of Prince Buldont from Ohranger become two separate characters with Buldont's Kasier form going to Prince Gasket.
First Name Basis: Every major villain will usually know the Rangers' names and tend to address them as such, but Gasket took it a bit farther. He refers to the Red Zeo Ranger not as "Tommy," but his actual first name ("Thomas").
Long Bus Trip: When Mondo finally cornered him, Gasket fled with Archerina and never returned.
Real Life Writes the Plot: The costumes for both him and Archerina practically disintegrated. Some parts were salvaged for later use, but the complete suits were irreparable.
Disproportionate Retribution: She developed a grudge against Kat (the Pink Ranger) very quickly (even though the two had never previously met), simply because she detested the fact that there was another female warrior around who liked bows and the color pink. (That's right. This was a rare case where the villain was actually upset with the realization that she and the heroine might be Not So Different.)
Guys Smash, Girls Shoot: Zigzagged. Archerina does tend to use a bow and arrows in combat, but on occasion she will use a sword as well.
Non-Mammal Mammaries: Just about every Power Rangers villain has these, but Archerina goes above and beyond. It's easy to understand why Prince Gasket pulled a Romeo and Juliet to get with her.