The name 'John' masc. proper name, c.1160, from Gk. Ioannes, from Heb. Yohanan (in full y'hohanan) lit. "Jehovah has favored," from hanan "he was gracious."  As the name of John the Baptist and John the Evangelist, it is one of the most common Christian given names.
There are approximately 130 saints with this name, or a common variant. Listed in Orthodox Wiki we have:
- St. John Chrysostom, Archbishop of Constantinople, also known as John of Antioch
- St. John III Scholasticus, Patriarch of Constantinople (February 21)
- St. John Climacus (March 30), author of "the Ladder" or "Climacus"
- Apostle John (May 8), also known as St. John the Theologian:
- St. John of Rila (October 19)
- St. John of Damascus (December 4)
- St. John of Kronstadt (December 20)
- St. John of Vilna
- St. John the Forerunner (January 7)
- February 24 - First and Second discoveries of the head.
- May 25 - The Third finding of the Head of St. John the Forerunner.
- June 24 - The Birth of St. John.
- July 23 - Synaxis of the Baptist, Gr. Σύναξις.
- August 29 - The Beheading of St. John, Gr. Απότομη Τιμ. Κεφαλής.
- September 23 - The Conception, Gr. Σύλληψις.
- October 12 - (Russian), transfer of hand to Gatchina
Not so common saints (not yet listed on OW):
- St. John (Beverley) of England (March 7)
- St. John the Chinese (June 11), see the Bio of St. Mitrof Tsi
- St. John De Montfort, no commemoration.
- OrthodoxWiki Note: God is Gracious"