Kirin
Kirin is creature type previously unique to the Saviors of Kamigawa. A Kirin is a flying Kami with aspects of a horse, a dragon, and a deer or goat. Before the Kami War, kirin were omens of good fortune and long life. It was said to appear with the imminent arrival or passing of a wise sage or an illustrious ruler.
There only is a cycle of five Kirin. Each of these rare legendary Spirit creatures has flying and a spiritcraft ability related to the casting cost of a cast spell.
These all play a role in the vignette The Meeting, where they discuss their stance on the Kami War and humanity as a whole.
More recently, Kirin have resurfaced in Khans of Tarkir, in the form of Alabaster Kirin. Like their Kamigawa cousins, these are illustrious omens, appearing on the awake of the arrival of an important figure (in this case, Sarkhan Vol). They are not part spirit.