To my knowledge there are only two active communities at the extreme southern tip: San Paolo Albanese and San Constantino Albanese, both part of the Eparchy of Lungro.
Previously, the community of Rionero in Vulture was an Arberesh (Italo-Albanian) city, however, the language and Greek Rite are no longer practiced there. If you go, I recommend Casa Brenna where we stayed in 2015. Many of the residents will admit to Arberesh ancestry, including the owner of this small B&B. If you want to hear the language spoken, nearby Barile, Maschito, and Ginestra have maintained it fairly well. We visited all three and spoke with the residents in Albanian. The language in Ripacandida also has significant Arberesh influence along with Greek. Brindisi di Montagna was another Arberesh settlement, near Potenza, which lost its language and Greek Rite services.
The Archbishop of Melfi is the one who ordered suppression of the Greek Rite in these towns and others under his jurisdiction in 1627. This well-known. For example, just across the regional border, in Taranto Province of the Region of Puglia, they've invited the clergy from the Eparchy of Lungro to celebrate the Greek Rite in their main church on their annual patronal feast day.
I lived over there for two years and worshipped and chanted in their churches. Would be happy to share more about the Greek Rite communities and their history in Italia. My paper is also posted on the Saint John Chrysostom Society's website hosted by byzcath.org