This sabbat is commonly known in many Neo-Pagan circles as Ostara.
A quick summary about Ostara-
Ostara was a fairly obscure Germanic diety who gained modern popularity after Aiden Kelly named the Spring Equinox after her.
So, how did the Spring equinox get named after Ostara? A prominent member of the Pagan community, Aiden Kelly was writing a book on religious holidays and calendars. He was inspired to craft a similar resource just for Pagans, which was shared in Green Egg in the 1970s.
What are some other Religious holidays celebrated this time of year?
Easter- Christianity
Holi -
Passover-
Ramadan-
About Naming Ostara, Litha, And Mabon
Leslie, Clare Walker., and Frank Gerace. The Ancient Celtic Festivals and How We Celebrate Them Today. Inner Traditions, 2008