Gulf of Aden
Gulf of Alaska
Gulf of California
Gulf of Carpentaria
Oman
Gulf of Fonseca
Gulf of Guayaqui
Gulf of Guinea
Gulf of Chihli
Gulf of Kotor
Gulf of Mexico (the biggest gulf of the world)
Gulf of Popua
Gulf of Taranto
Venezuela
are the only ones I can think of.
-Rifat Siddiqui
Gulf of Tonkin