The Facts (June 26, 2015)

Luci never made an appearance with BJ, David, Carlos, Juan, Kenneth, Jason, Julie, Shawn wearing glasses, Stella the Storyteller, Stephen or a shorter Baby Bop.
Mighty Morphin Power Rangers, Power Rangers Lost Galaxy, Power Rangers Lightspeed Rescue, Power Rangers Time Force and Power Rangers Wild Force are the only Power Rangers series where the gender of the Yellow Rangers for each series were changed to female, wherin their original Japanese counterparts are actually male.
As is commonly known now, despite the Yellow Ranger being a female within Power Rangers, in Kyouryuu Sentai ZyuRanger the Yellow/TigerRanger, ironically named "Boi", was male. Due to this, there is an obvious change in the physique of the Yellow team member when the show cuts to Sentai footage (this is most notable within Season 1). This is also why the Yellow Ranger does not wear a skirt, nor stand in girlish poses like the Pink Ranger does.
The Ninja and Shogun Ultrazords are the only Zord formations in Power Rangers history that are made from American footage. No suits or props were used in making them; the Bandai toys of each Zord were used to bring them to life on the show. The American versions of the toys were used for this, which presented some problems as the American versions are often noticeably different from the Japanese versions (and thus, the actual Zords on the show). For example, the left arm of the Japanese Shogun Megazord toy, the "Invincible General" from Ninja Sentai Kakuranger (and the real Shogun Megazord/Invincible General) is white. For some reason, the left arm of the Shogun Megazord toy was repainted pink for the American version to match the main five colors of the Rangers being used in the United States at the time (the U.S. was still using the Zyuranger colors of Red, Black, Blue, Yellow, Pink). Thus, the arm would suddenly switch colors whenever the Shogun Ultrazord was formed. Additionally, because the "Return of Titanus" version of the Titanus toy was used, the Ninja and Shogun Ultrazord formations mistakenly had the Dragonzord chest shield on the front of Titanus. Each formation, however, was used only once - Ninja Ultrazord destroyed the Face Stealer, and Shogun Ultrazord destroyed Dischordia, both events occurring in season 3.
Billy Cranston had unintentionally gained negative proton energy from the destruction of the Command Center. The power of the Gold Ranger couldn't be infused into Billy Cranston because, when the Command Center had blown up, Billy had absorbed an extremely high dosage of "negative proton molecules" which resisted the Golden power like two magnets (presumably the like poles of two magnets) put together.
Power Rangers Turbo was the first Power Rangers series not to have an Ultrazord of any type! This trend continued until Power Rangers: Operation Overdrive!
The omission of Rocky DeSantos from Forever Red is a storyline based one: Rocky was severely injured during the events of Turbo: A Power Rangers Movie as well as Rocky not actually having been the leader during his time as The Red Ranger. Also, Rocky's Ape Ninja Power Coin was destroyed.
Rocky DeSantos is the first Red Ranger not to be the leader of a Power Rangers team. He is notable for being one of the few Red Rangers (and the first Red Ranger) not to actually lead a Power Rangers team; others include Aurico and Wes Collins. But after Power Rangers Operation Overdrive ended, one Power Rangers fanfiction series (Power Rangers: Space Defenders) used two Red Rangers! They used a Red Ranger who is not the leader of a Power Rangers team and a Red Ranger who is the leader of a Power Rangers team. The first Red non-leader was Jason who stepped down as leader just before he left the team. This is because Zordon chose the new leader to be Tommy, the White Ranger. However, Rocky is the first Red Ranger who never led (however, his position as a red ranger wasn't second-in-command to Tommy it was Kimberly, the Pink Ranger).
Katherine Hillard is the only Mighty Morphin' Power Ranger never to see the Dinozords, Thunderzords, White Tigerzord or Dragonzord in action. She is also the only Mighty Morphin' Power Ranger that has never met Zack the Black Ranger or Trini the Yellow Ranger. She is also the only Mighty Morphin' Power Ranger to never encounter the Putties.
The main five Dairanger suits were never used for Power Rangers at all. Only the KibaRanger (White Power Ranger) suit was used for Power Rangers.
Lord Zedd is the first American-made villain that is only part of Power Rangers and not the Sentai Series. Others villains that would follow this are Divatox, Astronema, Scorpius, Trakeena, Ransik, Lothor, and Mesogog.