Another Star Alliance thread, first time checking out ex IST fares so I'm not even sure if they are good but I will post them anyway.
Most of the flights are operated by Lufthansa and they are connecting at FRA.

Please note that I have only stated 1 stopover flights if they were possible, note that there are cheaper fares but they have more than 1 stopover

IST - LAX - 1904$ (https://www.google.ca/flights/#searc...ST1LH1298;sc=b)

IST - SFO - 1825$ (https://www.google.ca/flights/#searc...=STAR_ALLIANCE)

IST - ORD - 1896$ (https://www.google.ca/flights/#searc...=STAR_ALLIANCE)

IST - DTW - 1986$ (https://www.google.ca/flights/#searc...STAR_ALLIANCEE)

IST - YYZ - 1671$ (https://www.google.ca/flights/#searc...=STAR_ALLIANCE)

IST - YUL - 1706$ (https://www.google.ca/flights/#searc...=STAR_ALLIANCE)

IST - NYC - 1607$ (https://www.google.ca/flights/#searc...=STAR_ALLIANCE)

IST - BOS - 1896$ (https://www.google.ca/flights/#searc...=STAR_ALLIANCE)

IST - IAD - 1617$ (https://www.google.ca/flights/#searc...=STAR_ALLIANCE)

IST - MIA - 1644$ (https://www.google.ca/flights/#searc...=STAR_ALLIANCE)

IST - YWG - 1865$ (https://www.google.ca/flights/#searc...=STAR_ALLIANCE)