The Sunshine Ponies joined the My Little Pony line in the UK in
1990, after first being released in North America in 1989. These
characters had streaks of colour-change fibres in their manes and
tails, which turned a dark magenta pink in sunlight. These streaks
often go frizzy with age, meaning that it can be hard to find
Sunshine ponies with good condition hair second-hand. The set
continued to be sold in the UK into 1991.
Each character also had a symbol spread across the haunches, in a
style similar but not the same as the Twice as Fancy release. They did not
have a small version of the symbol on the cheek.
The release in the UK and across Europe included four characters -
two earth, one unicorn and one pegasus. Mainsail, one of the earth
ponies, was the poster-pony for all 1990 sets, appearing under the
rainbow on all UK and European cards. The colour palette for their
cards was yellow, and Sand Digger featured on the front of all the
Sunshine Pony cards. Each pony was sold with a brush or comb, but
no ribbon. The cards were translated for releases in different
regions.
Mainsail Mint on Card
European style card (Benelux release), 1990
(Colour palette - yellow) Image from Shivhae
Sunshine Ponies in North America - Two Extra Friends
Although the release of the Sunshine Ponies in the UK and Europe
contained four ponies, the wider set sold in 1989 in North America
included two additional characters - Shoreline and Seaflower.
Unlike the four ponies sold in Europe, these two had pale pink
colour-change streaks, rather than white. This odd choice of a
sun-fading colour for a sun-colour change streak may have
influenced decisions by Hasbro Europe to cut them from the
release, as it was increasingly common to have sets of four not
six from 1990.
Shoreline Mint on Card US style card, 1989 Image from Shivhae
The cards from the North American line were very different from
the UK releases. Canadian versions were bilingual. I think this
version of the set was also available in Australasia but this is
not confirmed.