These sunnah prayer don't have a special name. Fajr, Zuhr, Asr, Maghrib, Isha are all names of compulsory prayers.

Which prayer is obligatory?

The daily obligatory prayers collectively form the second of the five pillars in Islam, observed five times every day at prescribed times. These are Fajr (observed at dawn), Zuhr prayer (observed at noon), Asr (observed late in the afternoon), Maghrib (observed at dusk), and Isha (observed after sunset).

Is it compulsory to pray Sunnah before Fajr?

The Messenger of Allah (PBUH) said: “No prayer is to be offered after Fajr prayer until the sun rises”, (Bukhari and Muslim). All the above-mentioned Ahadeeth clearly suggest that if the Sunnah Rak'ahs of Fajrare missed they are to be performed only after the sun has risen.