Over the My Little Pony generations Hasbro has chosen core character sets within each generation, but the treatment of 'main characters' has varied over time.
- (toy line)
The first G1 show, My Little Pony 'n Friends, featured a large number of ponies, with few ponies appearing in all episodes. However, Firefly, a character from the first special, was heavily featured in merchandise due to popularity. The non-pony characters Megan and Spike were the most consistently recurring characters on the show, though some of the ponies from the theatrical movie had repeating roles.
The second G1 show, My Little Pony Tales, featured seven preteen ponies as the main characters. They lived in a human-like world populated solely by ponies. Each member had their own toy, but none were released in the United States.
- Sundance (Sunsparkle)
- Light Heart
- Sweet Berry
Generation 2 is unique among the generations in that no TV shows or movies were made depicting its characters. (The first DVD releases of the G1 TV and movies were released during this time, very often with G2 artwork/ponies all over the packaging, which was/is confusing.)
Despite the lack of animated unity the main characters were established by featuring only the same four ponies together on all merchandise as well as occasional re-releases. Towards the end of the line these characters started being released under different names. They were also featured in the Euro comics(???).
Generation 3 began with eight core pony friends. Though many other character ponies were made, some of which even had several re-releases.
Late in the series Hasbro stopped making new characters and settled on only putting out seven different ponies repeatedly. These were dubbed "Core 7" by collectors, and were the characters re-styled to create G3.5.
- The Core 7
The core ponies (and a few variants there of) were the only ponies for G3.5.
- The Core 7
- Mane 6
The Mane Six are the six main characters of the TV show, My Little Pony: Friendship is Magic. In the early stages of development, each member was simply an updated version of a Generation 1 pony: Twilight, Applejack, Posey, Surprise, Firefly and Sparkler. However, they were redesigned using characteristics of G3 ponies due to trademark issues, as Applejack and Spike were the only trademarks from G1 to be retained. Earlier art from this point showed that Pinkie Pie was originally going to be a Pegasus, while Fluttershy would have been an Earth Pony, in keeping with their G1 inspirations, though their races were switched at an unknown point.
Until 2021, the Mane Six featured heavily in merchandise and advertising.
- Mane 5
While Generation 5's core cast is smaller than previous generations, it is especially unique for its inclusion of a stallion. The Mane 5 first appeared in My Little Pony: A New Generation.