One From Every Country
(or more correctly, one from every sub-entity!)
An example for each of the 1048 (of 1086) coinage types in my definitive 20th Century OFEC Collection
Note that they are in the same order as on the "20th Century OFEC Entities" page.
(I am in the process of adding images of each coin, please bear with me; in the meantime - get in touch!)

#	Sub-Entity Name	coins from	coins to	Political Designation	ruling authority	Den.	Unit	A.D. Year
0781	Sao Tome and Principe	1977	1997	Democratic Republic		2	Dobras	1977
0782	Sarawak	1900	1915	British Protectorate	Charles Brooke
0783	Sarawak	1920	1941	Ruler Change	Charles Vyner Brooke	50	Cents	1927
0784	Hejaz and Nejd	1925	1925	Monarchy & Sultanate	Abdulaziz bin Abdulrahman	1/2	Ghirsh	1925
0785	Hejaz and Nejd	1926	1926	Coinage Reform		1/2	Ghirsh	1926
0786	Hejaz and Nejd	1928	1930	Monarchy	Abdulaziz bin Abdulrahman	1	Ghirsh	1928
0787	Saudi Arabia	1935	1951	Monarchy	Abdulaziz bin Abdulrahman	1	Riyal	1950
0788	Saudi Arabia	1955	1960	Ruler Change	Saud bin Abdulaziz	4	Ghirsh	1956
0789	Saudi Arabia	1963	1963	Coinage Reform		1	Halala	1963
0790	Saudi Arabia	1972	1973	Ruler Change	Faisal bin Abdulaziz	10	Halala	1972
0791	Saudi Arabia	1976	1980	Ruler Change	Khalid bin Abdulaziz	25	Halala	1979
0792	Saudi Arabia	1988	1999	Ruler Change	Fahd bin Abdulaziz	50	Halala	1988