One of the well known female Buddhas in the Tibetan tradition is White Tara.
She is the Buddha of Long Life and sometimes appears together with Amitayus and Ushnisha Vijaya. The three of them are known as the Long Life Trinity.
White Tara is a female enlightened being whose function is to bestow long life, wisdom, and good fortune. If we rely on her with faith, she will protect us from the untimely death, and ultimately guide us to the