I have had luck with a few autumn blooming crocus that have reliably returned every year for over a decade to surprise me with their sudden appearance. These three all look very similar to me and could easily be substituted one for another. All are planted in gravelly, rocky soil that is extremely fast draining and bone dry very soon after any summer irrigation. They like moisture during their foliage growing season, now until the return of hot weather. Even though one is in part shade, I think all three would do well in bright shade to full sun.

Crocus goulymii is the third species, but hasn’t yet begun blooming. It has thrived in full sun.