It's only Sweet Notes. I had all four from new and she's the only one that's crimpy.
There are hair variations with the others, some have curly, some straight, some straight/curly combinations, some different shades of hair (blue v purple for Pretty Beat, red v red orange for Tuneful) depending mostly on where they were sold. But no other crimped ones.
The only other crimped ponies I can think of right now are the Great Hair girls.