One of the few Pokemon revealed during the dubious 24 hour livestream Pokemon hosted a few days ago has had more information revealed on the official website.
Galarian Ponyta (and by extension, Rapidash) are Shield-exclusive takes on the Gen One Pokemon by the same name, and appear to be based on the mythological Unicorn (who is, it happens, Scottland’s national animal).
They are Psychic-types, and their mane glistens a pastel rainbow due to passively absorbing life energy from its surroundings. They are native to a particular forest in the Galar region, and they have the special ability, Pastel Veil. Pastel Veil makes them immune to the Poison status effect, and make allies on the field immune, too – they can even heal Pokemon who have been poisoned.
This sounds like a pretty cool Pokemon in our opinion! A video of the reveal may be found below.