RAINBOW BABY PONIES
Though the adult Rainbow Pony sets in the early years of My Little Pony had been widely successful, and the Rainbow Curl ponies had carried the theme forward into the 1990s, it was not until 1991 that Hasbro released their first set of Baby ponies on the rainbow theme. Unoriginally but accurately titled 'Rainbow Baby Ponies', this set of four characters included one unicorn and one pegasus, the other two being earth ponies.
The set was sold internationally, and in the My Little Pony comics and backcard stories of the UK, these babies were generally the charges of the Rainbow Curl ponies, living with them somewhere on Rainbow Mountain.
There are some minor variations within this set, in particular Baby Starbow - more on her page.