Monastery of Portaitissa is just one of the landmarks located 9.7 mi (15.6 km) from central Soufli, so you might want to stop by for a few pics during your trip.
If museums are on your list of things to see in Soufli, then you might want to head to Silk Museum. If you want to see more of the museums in Soufli, you can easily walk to Folk Museum.