According to Pirke Hechaloth, the angel Zahabriel is a guardian angel stationed in the first Heaven.
Zanziel is one of the many celestial guardians at the gates of the West Wind, and is referenced in Ozar Midrashim II.
Zevudiel is a guardian angel of the first Heaven. There are seven guardians of the first Heaven in total.
Zikekiel is one of the angelic guardians of Abraham. He is also one of those who acted as Abraham’s teacher.
Zortek is one of numerous guardian angels who protect the first Heaven. Zortek is an angel from hechaloth lore.
Zuriel is one of the seventy amulet angels who watch over mothers and children during childbirth. Zuriel is the angel of the month of September and one of the regents of the zodiac sign of Libra.
(Faber. L. 2010. The Book of Angels. London. Arcturus Publishing Ltd.)