The Rockin'/Rocking Beat Ponies - Ponyland's first live band.

"Sing a song of Ponyland, the ponies sing and play. Four Rocking Beat Ponies welcome you today!"
                                                                                                                            Rocking Beat Pony Backcards, UK

The Rockin' Beat Ponies (written Rocking Beat in the UK packaging and promotional material) were introduced in the UK and in Europe in 1992.

They had been released in the North American line the year before, on bright green cards with communal backcard stories. In the UK and in Europe, they were sold on lavender purple cards with darker purple borders, in keeping with the style template of 1992. Tuneful, the unicorn from the set, was the year's promotional pony and featured on all 1992 cards. Half Note was the set's mascot, appearing on the front and back of the cards.

Tuneful, Mint on Card
UK, 1992
Palette: Lavender purple
Image donated by ebay seller

Each pony was sold with a plastic guitar brush with a gold strap, and a (more or less) matching ribbon. Ribbons were not sold with this release in North America.

There are variations to be found in this set, in at least three of the ponies (I have not confirmed Sweet Notes). Tuneful and Pretty Beat are the most visible, with different shades of hair and body. Half Note is more subtle. The below image demonstrates these variations, but you can find out more about them on the individual pony pages.

Variations in the Rockin' Beat Line between 1991 and 1992

The image at the top of the page comes from the UK and European insert and backcard, but the ponies pictured in it are more often found in the North American release. This is common in promotional material with ponies sold in the UK or in Europe at a delay to those sold in North America, as Hasbro normally posed their photos using what was already available - even if it wasn't strictly correct.