Here are the Russian Orthodox saints that start with the letter "I," with feastdays where applicable:
- Ignatius the Godbearer, Bishop of Antioch
- Ignaty of the Far Caves, December 20
- Ignaty Raksha of Hebron, Abbot
- Ignatius Brianchaninov, Bishop
- Igor the Prince of Chernigov and Kiev
- Innas, Pinna, and Rimma the Martyrs
- Innocent of Alaska, March 31and September 23
- Innocent of Irkutsk
- Innocents Slain at Bethlehem, December 29
- Irene, Agapia, and Chionia the Martyrs.
- Irene of Lesbos, Bright Tuesday
- Irina the Martyr of Balkan
- Isaiah, Martyr in Cilicia, February 16
- Isaiah the Wonderworker of the Kiev Caves, May 15
- Isaakios of Dalmation Monastery, December 30
- Isaaky the Fool-for-Christ of the Kiev Caves, February 14
- Isaaky the Recluse, February 14
- Isidora of Egypt, May 10
- Isidore, May 14
- Isidore of Rostov, May 14
Source: http://www.gnisios.narod.ru/lives.html