This list is far from complete.
There is not always an 1:1 relation between a place etc. in Roman times and a name in our days.
Sometimes a people giving their name to a place and that place are combined.
Some names are followed by a link to a site with that title
I tried to find suitable sites in English, but did not always succeed.
If you know better sites, please let me know.

Adria(3) / Adriatic(3) / Adriatic Coast(1) / Adriatic Sea(12) / Hadria(4) / Sea of Hadria(1) Aegean Sea(1) / Aegean(1) Arabian Gulf(1) Atlantic(5) / Atlantic sea(3) / Western Sea(3) Baltic Sea(0) / Mare Suebicum(0) / Suevian Sea(1) Black Sea(0) / Euxine Sea(3) / Pontic Sea(2) / Pontus(2) / Pontus Euxinus(0) / Sea of Pontus(4) Caspian Sea(6) / Hyrcanian Sea(3) Dead Sea(0) Etruscan Sea(1) Gallic Gulf(1) German Sea(1) / German Ocean(1) Great Sea(2) Greek sea(1) Indian Ocean(2) Ionian Sea(10) Jewish Sea(1) Mediterranean(6) Northern Ocean(3) Red Sea(10) Sea of Galilee(2) / Lake Kinneret(0) Sicilian sea(1) Strait of Gibraltar(0) / Fretum Gaditanum(0) / Strait of Gades(2) Straits of Messina(1) Syrtes(3) / Syrtis(1) Tyrrhene(1) / Tuscan Sea(4) / Tyrrhenian Sea(5) / Tyrrhenian waters(1)