All of the Mane Six evolve to their adult selves at level 18, then again to their Grand Galloping Gala dress form at level 32. The exceptions to this are Applejack (which evolves at levels 16 and 36) and Rarity (whose Gala evolution is at level 36).
Nightmare Night Costumes - will use a "nightmare stone", like a Moon Stone.
Discord Ponies - alternate form possibly found on the Sevii islands.
Hearth's Warming Eve Costumes - Alternate forms based on the first ponies to have settled Equestria.
- In Duskshine's Alpha 0.2, Fluttershy and Rainbow Dash - the two middle ponies on Oak's table - were still called Squirtle. This glitch only happened when you observed their pony ball on the table.
- Rarity, Applejack, and Fluttershy are all catchable in both versions in Duskshine's Alphas 0.2 and 0.3 at Route 25 due to a strange glitch.
- The version in which the mane six were available on was switched when Flutteryay took over. Previously, Pinkie Pie, Rainbow Dash, and Twilight were found in Dusk, and Applejack, Rarity, and Fluttershy were found in Dawn.