Main Drain
An energy draining robot monster used by the Machine Empire. In battle, he shot his drain tubes underground and attached them to the Zeo Megazord. He was the first monster to ever break a Megazord saber, which broke in two after Main Drain electrocuted the Zeo Megazord. He was himself destroyed by Red Battlezord.
"Inner Spirit" & "King for a Day, Part 1"
A robot boxing monster who turned Adam into a trophy. In the first confrontation, Punch-A-Bunch managed to eject Tommy from the Red Battlezord, but destroying his own glove in the process. Later there was a boxing-style battle that took place, but the Machine Empire cheated. Soon the boxing ring was destroyed by the Rangers in the Command Center and the fight was fair again. Eventually destroyed by Red Battlezord. He is later seen as part of the audience in the Machine Arena.
Mace Face
A spiked robot monster used by the Machine Empire. He had two forms: his regular spiked monster form, and the form of a spiked ball. He was the first monster to be destroyed by the Zeo Mega Battlezord. He was later seen in Prince Gasket's Machine Arena and lastly fighting the Phantom Ranger for the Machine Empire.
"Found and Lost," "Brother, Can You Spare An Arrowhead?," "King for a Day, Part 1" & "Countdown to Destruction, Part 1"
Autochthon ('Aw-Tock-thon') ancient evil spirit, who was also known as Top Gun, accidentally awakened by Tommy's brother David Trueheart. He originally overpowered the Zeo Megazord and Red Battlezord, but was ultimately destroyed by Zeo Mega Battlezord.
"Brother, Can You Spare An Arrowhead?"
A deceptive robot monster created from scrap parts by Klank and Orbus. He was to make friends with the Power Rangers, aiding the Rangers on Earth with different situations. He even saved a little girl's dog from being run over by a car on the street. Later, King Mondo and an army of Cogs and Quadrafighters launched an attack on the Rangers and Defector. Klank then arrived to cause pain to Defector with a remote control. Rocky went to check on him, and he responded by attacking the Rangers. Rocky then went on the attack, and soon afterwards Tommy called on the Defender Wheel. Rocky, who felt responsible for the whole thing, volunteered to pilot the Defender Wheel, destroying him.
"Trust in Me"
Drill Master
Originally a monster from Adam's dream who battled,alongside a Quadrafighter in land mobility, and was defeated by Tommy, Drill Master was built for real by the Machine Empire as one of the newly improved robot warriors that received the Neo-Plutonium Armor. He was destroyed in an underwater battle by Super Zeo Zord IV.
"It Came From Angel Grove" & "A Golden Homecoming"
Googleheimer Toy Robot
A robot toy monster used by Prince Sprocket, that was a deadly adversary. The Rangers did take him down with the Zeo Cannon, but it wasn't enough as Klank and Orbus made the monster grow. During the Megazord battle, the monster trapped the Zeo Megazord in what looked like silly string. The Red Battlezord came to the rescue and bailed out the Zeo Megazord. After the two zords merged to become the Zeo Mega Battlezord, playtime was definitely over for the monster when he got decimated by the Zeo Mega Battlezord. He didn't have a proper name.
"Bulk Fiction" & "King for a Day, Part 1"
Wrecking Ball
A robot wrecking ball monster controlled by Prince Sprocket as a birthday gift to Sprocket. Sprocket controlled the monster's movements at the Machine Empire home base for a while, then King Mondo sent Wrecking Ball down to Earth to attack Angel Grove. Wrecking Ball landed on Earth as a giant. Tommy fought him with the Red Battlezord and defeated him.
"Song Sung Yellow" & "King for a Day, Part 1"
Admiral Abominator
A robot admiral monster who held Bulk and Skull prisoner in the forest until the Rangers came to free them. The admiral wielded a sword and also had a bed of spikes built in underneath his coat. He tried to impale Katherine with it, but Tommy saved her, and Katherine knocked him out with her shield. Orbus made him grow. The Red Battlezord delivered a flurry of punches to the admiral, and then the Zeo Megazord, armed with Zeo 1 Power Helmet, blasted the admiral. The Rangers then destroyed him with the Zeo MegaBattlezord. He later appears in Divatox's army on the planet Gratha.
"Game of Honor," "King for a Day, Part 1" & "Countdown to Destruction, Part 1"
He was sent to ambush the Rangers during a divide and conquer tactic. When it looked like Wolfbane had the Rangers beaten, he and the Cogs were teleported away in order for King Mondo to figure out what was heading for Earth. Later, as the Rangers had split up again to track down the UFO, they were attacked again by Wolfbane and the Cogs. Suddenly, Gold Ranger appeared for the very first time and was able to take out the Cogs and Wolfbane. Wolfbane became big and fought the Zeo Megazord and then the Red Battlezord. Wolfbane had more than enough power to knock the Rangers out of their zords. The Gold Ranger then exterminated Wolfbane with Pyramidas.
""The Power of Gold"