Check out this month's or last month's Airliner World or Airliners magazine can't remember which lol sorry.. for a list of current 707 operators and the very small number, (in some cases only 1) that each operator still has left. It doesn't say how many are still in active service, so the number might be even less.
Saha Air, Azza Air Transport, Spirit of Africa, Koda Air, Johnson Air, Wimbi Dira Airlines, First International Airlines, LADE (airline operated by the Argentinian AF
), Royal Jordanian, Lybian Arab (used as VIP transport), Skymaster and BETA.
Those are about the only civilian 707 operators left and maybe one or two more that I can't remember that were on the list. The rest were private, VIP, and military aircraft.