1983:
Earth Ponies
"Earth" Ponies, defined as ponies who did not have a unicorn's horn or a pegasus pony's wings, were basically your average, normal little ponies, kitted out for gallops across the field and not much more. Though all ponies with no horn or wings are generally referred to as "Earth" ponies or "Earthlings", Hasbro never actually gave a set that name. They were simply "My Little Pony".
Yet "Earth" pony was a Hasbro term. These early six little ponies featured some innovative new styles - some of which would never be used again. Bubbles and Seashell, who would only be sold this year, were made in a sitting down pose. Though variant ponies made in other countries have mimicked this pose, in the ordinary line there are no more sitting down ponies. (It's believed this is because sitting ponies were hard to put in ponywear, due to the arrangement of their back hooves). Both Bubbles and Seashell also sported a blaze on their noses - another style never again copied.
UK packaging for 1983-4 Earth Pony set featuring Flat Foot Pony artwork on the front (Blossom's card)
The release of these ponies in the UK predate Hasbro UK's official records, and this is represented in many ways in the style of packaging used for this year. The backcards for this set in the UK featured the Flat Foot Ponies on the front using the North American artwork. The back, however, was distinctly marked "Hasbro UK", and, instead of featuring all the Unicorns and Pegasus ponies for this year as well as the Earthlings, it simply featured the six earth ponies (as the others didn't get a UK release).
Backcards of the 1983-4 Earth Pony release in UK and North America
Blossom's card also mentions Hasbro UK in the bottom right corner, but beneath this is the copyright to Hasbro USA. Although the artwork is based on the North American art, it is clear that Hasbro UK had some of their own input on the art. Blossom has a bow in her mane and a twisted/braided tail, and Applejack also has a braid in her tail. Bow Tie's tail has been braided and is hidden behind Bubbles in the UK graphic. It seems probable that the artists for the UK were given the US image to work from, but ultimately amended it in their own style.
The insert for 1983/4 (we generally assume 1984) is very very hard to come by, as it appears to have only been sold with playsets (thanks to Gizmo for this theorising!). This set appear on it, however, with the tag that this insert shows the "whole" collection of My Little Pony available in the UK that year. For some reason, they were all shown with versions of the Grooming Parlour brush, but there is no evidence they were actually sold with these.
1984(?) insert, UK: Earth Ponies
Applejack and Bow Tie would go on to become some of the best known and best loved little ponies, and would see sundry re-issues. Both ponies featured the year's new 'Shy' pose, and both ponies had freckles on their cheeks. Hasbro obviously liked freckled ponies, as this concept was used again and again as the line progressed.
Cotton Candy and Blossom were retained from the first year, though both were now undoubtedly concave foot ponies. It is fairly certain that both versions of these two ponies were sold in the UK.