The Other Darrin: This trope was not kind to the Swordbot Brothers. Magician, Fistbot, Spitbot, Minotaurbot, Wolfbot, Amphibidor also. Played around with when Zelton turned into Graybot and Metalbot.
Once, the Swordbot Brothers even switched voice actors from the previous appearance. But it seems they never got the same VA twice, and they kept getting prominent appearances (rather than the standard "hanging out in the background in Grimlord's lair sequences 'til it's your turn as Monster of the Week" situation.) The last voice actor ended up playing both characters.
The Other Marty: Jason David Frank was originally set to play Adam Steele in the unaired Cybertron pilot. A second pilot was also made which featured Professor Hart being played by a Caucasian. Brad Hawkins was cast as Rocky the White Ranger on Power Rangers. Saban realized that replacing Frank on Power Rangers was too risky so Frank returned to Power Rangers as Tommy in the role of the White Ranger and Hawkins stepped into the role renamed Ryan Steele. The name Rocky ended up being reused for for the second Red Ranger on Power Rangers.
Prop Recycling: The suits used for the battle grid fights were based on the spandex suits used in MMPR, notably using the Red Ranger helmet mold from MMPR retooled/repainted to remove the dino details and to look closer to the trooper suits.
Recycled Script: Not only the underground lab raid, but the brief Once per Episode sequence of a giant floating head thingy that would attack Ryan, only for his super robot to come and shoot it down throughout Season 2. There's no explanation given as to where either of these come from or why they're not used for more than this sequence.
The Cybertron pilot also shows that the series was originally intended to be a stand-alone adaptation of Metalder. It was only after Jason David Frank was replaced by Brad Hawkins that the series was revamped into a team show and the Spielban footage was brought in for the two additional main characters (since Metalder was a lone hero, whereas Spielban had a costumed female sidekick). By that point, Saban was also using footage from two different Super Sentai series for MMPR (Zyuranger and Dairanger).