Bad Export for You: The Japanese release of the first two games was plagued by numerous issues, including numerous glitches, a nearly uncontrollable camera, and most inexplicably, signs scattered literally everywhere that caused "helpful" tips to pop up whenever they were hit with Spyro's flame, accidentally or otherwise. Understandably, the first two games did not do well in Japan, and as a result Year of the Dragon never made it there.
Also, in the original trilogy, Spyro was first voiced by CarlosAlazraqui (probably best known as the voice of the Taco Bell dog and Rocko, not to mention a certain crazy teacher obsessed with finding "FAIRY GODPARENTS!!") before voice duties switched to Tom Kenny. In the first game Clancy Brown also provides some dragon voices.
Spyro is voiced by Elijah Wood in the new trilogy. You will recognise his voice.
The Electrolls in the level "Hurricos" in Spyro 2 have the exact same voice of SpongeBob SquarePants. Even weirder, some of the dragons in the first game are voiced by Mr. Krabs, and Zoe in the third game is voiced by Sandy Cheeks.
Executive Meddling: Heck, this whole franchise was built around this trope. Originally, Sony of America wanted to create a "kid friendly game and character for the Playstation" (considering the games at the time were... ratheradultandteen oriented), hence the creation of the franchise, in which Insomniac never even had the full rights of in the first place, which resulted after Year of the Dragon's release that the franchise was sold and then became a Franchise Zombie until purchased by Sierra, who being way past their time ended up being bought out by Activision games.
The Other Darrin- In the first game Spyro was voiced by Carlos Alazraqui, then by Tom Kenny and Jess Harnell, then Elijah Wood in Legend of Spyro and finally Josh Keaton in Skylanders. Within The Legend of Spyro trilogy, Sparx changes voices in every game (David Spade, Billy West, and Wayne Brady), and Cynder goes from being Cree Summer to Mae Whitman, then Christina Ricci, and finally Tobie La Salandra in Skylanders.
What Could Have Been: Elora was meant to be originally a centaur instead of a faun, and Sgt. Byrd was a pig instead of a penguin. Sheila had horns, wore a t-shirt, and had boxing gloves in early concept arts. There was going to be a MMORPG based off the Legend Of Spyro series but it got scrapped for Skylanders. Elora was meant to appear in Attack of the Rhynocs and Season Of Ice but was scrapped due to time constraints.
There were plans for an Agent 9 spinoff. One project was a complete reboot, where Agent 9 was called "Prime 8" and had a realistic redesign. The other was more faithful to the original.
Spyro was originally green and his name was "Pete" at one point in development.