These came in 3 packs in a variety of colors and poses as part of the Magic of Pegasus line. They are approximately 3″ long. There are also fakie versions often found at dollar stores.
Laying down:
Rearing:
All 4 hooves on ground:
Raised front hoof:
In the early 2000’s, there were also Barbie mini horse 3-packs that the Magic of Pegasus minis replaced. These were slightly smaller, made of a softer plastic than the hard plastic pegasi.