Here are some websites and videos about different Hellenic Languages and cultures.
The dialect of Greek spoken throughout Greece, Cyprus, and the Greek diaspora.
https://en.m.wikipedia.org/wiki/Greek_language
https://en.m.wikipedia.org/wiki/Modern_Greek
https://en.m.wikipedia.org/wiki/Greek_alphabet
https://en.m.wikipedia.org/wiki/Greeks
https://en.m.wikipedia.org/wiki/Greece
https://www.omniglot.com/writing/greek.htm
https://www.duolingo.com/course/el/en/Learn-Greek-Online
https://www.youtube.com/user/greekpod101
https://youtu.be/OIB5SKG3no0
https://youtu.be/7o8NcTiXGYI
https://youtu.be/mQyL3LgJwXA
The modern descendant of Doric Greek (the language of Sparta). Surviving only in a few villages in southern Greece.
http://www.tsakoniandialect.info
https://en.m.wikipedia.org/wiki/Tsakonian_language
https://www.omniglot.com/writing/tsakonian.htm
https://youtu.be/321JX9QiME0
https://youtu.be/0nxD4GDJXCw
A variety of Greek spoken in southern Italy. It has heavy influence from Italian and the surrounding languages.
https://en.m.wikipedia.org/wiki/Griko_dialect
https://en.m.wikipedia.org/wiki/Griko_people
https://www.omniglot.com/writing/griko.htm
https://tribalingual.com/courses/greko-2/
https://youtu.be/ofs4ARx-QN4
https://youtu.be/LSktx_kr4ww
https://youtu.be/dHCf9k3u2IQ
https://youtu.be/C0p05Wdafa8
https://youtu.be/ofs4ARx-QN4
https://youtu.be/PhMxt9nZ3tM
A dialect of Greek spoken in northern Anatolia and in a few Greek villages, due to the population exchange.
https://en.m.wikipedia.org/wiki/Pontic_Greek
https://en.m.wikipedia.org/wiki/Pontic_Greeks
https://en.m.wikipedia.org/wiki/Greek_genocide
https://en.m.wikipedia.org/wiki/Pontus_(region)
https://www.omniglot.com/writing/pontic.htm
https://youtu.be/vHWpv_3NmBs
https://youtu.be/UcAYP4irSyQ
https://youtu.be/kVHgdgKR6tw
https://www.youtube.com/playlist?list=PL630-q6V5tZBoP1gtbZyP1vouwsdzmTn9
The Greek spoken by the Yevanic Jews of Greece, also called the Romaniotes. It is kind of like Jewish English, from what I’ve read, it’s mutually intelligible with Greek, but it has some Hebrew words thrown in. I still feel like it’s really interesting and worth mentioning.
https://en.m.wikipedia.org/wiki/Yevanic_language
https://en.m.wikipedia.org/wiki/History_of_the_Jews_in_Greece
https://en.m.wikipedia.org/wiki/Romaniote_Jews
https://www.omniglot.com/writing/yevanic.htm
https://youtu.be/9NRqqjflY7Y
Σάννα/Cypriot Maronite Arabic
Sanna is Arabic not Hellenic, but it is heavily influenced by Greek. It is spoken in Cyprus, and one of the National languages.
https://en.m.wikipedia.org/wiki/Cypriot_Arabic
https://en.m.wiktionary.org/wiki/Appendix:Cypriot_Arabic_Swadesh_list
https://www.omniglot.com/writing/cypriotarabic.htm