Applejack mane = Fluttershy coat = Rainbow Dash yellow mane stripe

Fluttershy mane = Pinkie Pie coat = Sweetie Belle mane (pink)

Applejack body outline = Scootaloo outline = Rainbow Dash orange mane stripe

Twilight pink mane stripe = Pinkie mane

Twilight purple mane stripe = Rainbow Dash purple mane stripe

I may have missed some, but the point is that colorful ponies often share colors in their palettes and that’s pretty cool! (Except Rarity, because she’s one of a kind.)