Many surviving clones remained in active service to the Empire. Many were killed when they were sent to Kamino to destroy the cloning facilities. Imperial clones fought againsts Kaminon clones and thousands were killed, and Kamino raized. If I remember correctly some clones left service and sought out existances as mercenaries and hermits and such. Boba Fett found a clone trooper living on Geonosis and killed him so he could talk his vital organs, as Boba's were secumbing to clone degeneration.