The Pale-legged Marbled Bush-Cricket was described in 1976, it is, or maybe was, restricted to its type locality, apparently near the Linoseli spring in the Lefka Ori Mountains on the island of Crete, Greece.
The species was apparently only ever found once and is now believed to be extinct.
The Lake Prespa Mudsnail was described in 1973, it was apparently endemic to Lake Prespa, an quite ancient lake that is located between Albania, Greece, and Macedonia.
There are no recent records of this species and it is believed to be possibly extinct.
Another species of that genus, which was also presumed extinct, was rediscovered in 2013. 
 Magdalena Szarowska; Sebastian Hofman; Andrzej Falinokski: Vinodolia fiumana Radoman, 1973 (Caenogastropoda: Rissoidea): rediscovery and relationships of a species presumed extinct. Folia Malacologica 21(3): 135-142. 2013
The Santorini Glass Snail was described in 1987 based on subfossil shells that were found in the volcanic deposits of the island of Thira, also known as Santorini, in the southern Cyclades Islands, Greece. 
The species seems to have been wiped out by a volcanic eruption that happened at 1450 BC., the same eruption that may have led indirectly to the collapse of the Minoan civilization on the island of Crete, 110 km to the south of Thira, through a gigantic tsunami.
 A. Riedel; A. Norris: An undescribed species of Zonites from the Island of Santorini, Greece. Journal of Conchology 32(6): 377-378. 1987
The Macedonian Freshwater Snail was described in 1978, it was endemic to Lake Dojran between Greece and the Republic of North Macedonia, where it was found near the shore in depths between 0 to 50 cm.
The species begun to disappear in the 1970s when the level started to sink due to increasing extraction of lake water for agriculture that led to the complete loss of the species’ habitat.
The last living individuals were finally found in 1992, and the species is likely extinct.
The story of the Macedonian Freshwater Snail, however, is not over yet: during the most recent surveys that took place in 2012, only empty shells were recovered, yet some of them appearing very fresh, leading to the hope that some popualtions may still linge somewhere in the Lake. 
 Canella Radea; Aristeidis Parmakelis; Vassilis Papadogiannis; Despoina Charou; Kostas A. Triantis: The hydrobioid freshwater gastropods (Caenogastropoda, Truncatelloidea) of Greece: new records, taxonomic re-assessments using DNA sequence data and an update of the IUCN Red List Categories. ZooKeys 350: 1-20. 2013
The subspecies discussed here, was described in 1997 based on subfossil remains, it inhabited at least the two islands of Dyo Adelfoi and Sirna in the Dodecanese Islands in the southeastern Aegean Sea of Greece.
The ‘nominate’ form of this species appears to be nearly extinct as well, it seems to survive only on the island of Megali Zafrano. These island forms, however, most likely represent(ed) distinct subspecies as well.
Unfortunately, it is apparently impossible to find a good map of Greece’s islands or a actual source for binding official island names ….
This species, which was described in 1936, is apparently only known by subfossil remains which apparently were recovered from three of the Cyclades Islands, Folegandros, Sifnos as well as Sikinos; each island might have had its own endemic subspecies. 
It is, however, surprisingly difficult to find more information about this species.
 Adolf Riedel: Revision der Gattung Zonites Montfort (Gastropoda, Zonitidae): türkische Arten. Nebst Ergänzungen und Verzeichnis aller Zonites-Arten. Annales Zoologici 41(1): 1-51. 1987
The island of Tilos is located between the islands of Kos and Rhodes in the eastern Aegean Sea.
This island, like all of the islands in the Mediterranean Sea, once harbored its own, endemic fauna, including dwarfed animals like this endemic Elephant, whose fossil remains were already discovered in the 1970s.
The Tilos Dwarf Elephant was slightly larger than most other dwarf elephants known from other Mediterranean islands, it reached a shoulder height of about 1,2 to 1,6 m and a length of about 1,9 m.
The species died out around 3500 B.P., meaning it survived at least until the beginning of the Aegean Bronze Age. It was probably directly hunted to extinction. 
 G. E. Theodorou; N. Symeonides; E. Stathopoulou: Elephas tiliensis n. sp. from Tilos island (Dodecanese, Greece). Hellenic Journal of Geosciences 42: 19–32. 2007