Which of the following prayers is not observed between Isha and Fajr?

Tahajjud, Shaf’i and Witr are all night prayers prayed after Isha and before Fajr. Shaf’i is the two rak’ah that come before Witr.

Salatul Istisqa is the prayer for rain. It is prayed in the open, in the daytime, after sunrise. So it is the one not observed between Isha and Fajr.