Hey I have for you 5 little known but must visit places in Goa 1- devil's canyon 2-kadamba dynasty temple - Mollem national park
3- scuba diving- grande island
4- harvalem falls 5- querim (keri) beach
this places is for real traveler happy traveling
If you are going for beaches , there are many off beat ones. Try butterfly beach, St Francis church, Dona Paula view point, Old Goa and Chapora fort would be my suggestions. Cheers.