The following post contains the historical flags - which were originally in the opening post, before I replaced that with the index of post links.
Before I post the images, though - a quick disclaimer. I'm well aware that some of these flags represent far-left or far-right regimes, which did horrible things in the name of their ideology. Thus,
the fact that I have created these images is not an indication of support for any of these regimes, or anything they did. Rather, these are being posted
only for use in historical contexts, i.e. when discussing the countries themselves, or individuals or groups connected with those countries, at the time when these flags were in use.
Any other use of these flag images is forbidden (and indeed, there are certain flags here whose use in a non-historical context may violate our "
Adult and Prohibited Content" policy).
With that out of the way, I'll post these flags in alphabetical order of country, starting with:
Austria-Hungary
Here we have the civil ensign, that was in use from 1869 to 1918:

([flag=austria-hungary-1869])
Biafra
The unrecognised state of Biafra only ever had one flag, which was used between 1967 and 1970:

([flag=biafra-1967])
Brazil
Here we have the flag of the Empire of Brazil. This exact version was used from 1853 to 1889, but the basic design was in use from 1822:

([flag=brazil-1853])
Bulgaria
Between 1947 and 1990, the flag of the People's Republic of Bulgaria had a coat of arms in the canton. The exact arms changed over the years - but this emoticon represents all of them:

([flag=bulgaria-1947])
Byzantine Empire
The Byzantine Empire pre-dates the modern idea of "each nation having its own national flag" - but, this symbol was used to represent Byzantium on some naval charts from around 1375:

([flag=byzantine-empire-1375])
Cambodia / Kampuchea
The following flag was used by Cambodia (officially "Democratic Kampuchea") during the reign of the Khmer Rouge, between 1976 and 1979. The same basic design (with a different building) was subsequently used until 1989:

([flag=kampuchea-1976])
Canada
Before adopting the familiar 'maple leaf' flag in 1965, Canada had a series of Red Ensign-based flags. The one I've posted here was in use between 1921 and 1957:

([flag=canada-1921])
China
Two flags here. First is the flag of the Qing Dynasty, adopted in 1889, and used until 1912. Second is the "Five-colored Flag", adopted by the Republic of China in 1912, and used until 1928:

([flag=china-1889])

([flag=china-1912])
Confederate States of America
Two flags here. First of all is the 'Stars and Bars' flag used between 1861 and 1863. Then, we have the 'Blood-stained banner' flag used from March 1865:

([flag=csa-1861])

([flag=csa-1865])
Danzig
As with Biafra, the Free City of Danzig only ever had one flag - which it used for the entirety of its existence from 1920 to 1939:

([flag=danzig-1920])
Democratic Republic of the Congo (Zaire)
Just one flag here. It's the flag used when the country was known as Zaire, from 1971 to 1997:

([flag=zaire-1971])
Egypt
Two flags here. The first was used by the Kingdom of Egypt between 1922 and 1953 (and co-officially by the Republic of Egypt between 1953 and 1958), while the second was introduced in 1958 (for Egypt's short-lived merger with Syria under the "United Arab Republic" name), and retained until 1972:

([flag=egypt-1922])

([flag=egypt-1958] or [flag=uar-1958])
Ethiopia
Just one flag here. It's the flag with the Lion of Judah, used between 1897 and 1974:

([flag=ethiopia-1897])
France
Here we have the lighter version of the French Tricolour, used between 1974 and 2020. (This is still co-official with the darker version; however, since 2020, the darker one has taken precedence, and therefore is the one used as the default French flag emoticon on TCH):

([flag=france-1974])
Germany
Five flags here. First is the imperial banner of the Holy Roman Empire, used from around 1430 to 1806. Next is the flag of the German Empire, used from 1871 to 1918 (and again from 1933-35). After this, we have the state flag of the Kingdom of Prussia (used from 1892 to 1918), and the flag of the Saar Protectorate (which existed from 1946 to 1956). Finally, we have the flag of East Germany, used from 1959 to 1990:

([flag=hre-1430])

([flag=germany-1871])

([flag=prussia-1892])

([flag=saarland-1946])

([flag=east-germany-1959])
Of course, there is another former German flag that's quite obviously missing here. Before anybody's asking about it, I have no plans to add it - partly because some countries have strict rules regarding its display (and I would rather not open myself up to legal trouble), and partly because it has so much more potential for misuse than any of the other flags in this thread. Sorry!
Great Britain
Only one here. It's the flag of the Kingdom of Great Britain, used between 1707 and 1801:

([flag=great-britain-1707])
Honduras
One flag here. This was used from 1949 until 2022, and it's similar to the current flag, but with a darker shade of blue:

([flag=honduras-1949])
Hong Kong
Another one with only one. This was the fourth colonial flag, used between 1959 and 1997:

([flag=hong-kong-1959])
Iran / Persia
Only one here. It's the 'lion and sun' flag, used between 1907 and 1980:

([flag=iran-1907])
Italy
Only one for this one too. It's the flag of the Kingdom of Italy, used between 1861 and 1946:

([flag=italy-1861])
Libya
Another country where I have just one flag. This one was used by the Great Socialist People's Libyan Arab Jamahiriya, under the reign of Colonel Gaddafi, between 1977 and 2011:

([flag=libya-1977])
Netherlands Antilles
The following flag was used by the Netherlands Antilles from 1986 until the territory's dissolution until 2010. (A flag with the same basic design, but with six stars instead of five, was used from 1959 until the departure of Aruba in 1986):

([flag=netherlands-antilles-1986])
Portugal
Just one flag here. It was used between 1830 and 1910:

([flag=portugal-1830])
Romania
Yet another one where I have just one flag. Versions of this design were used by the Socialist Republic of Romania between 1948 and 1989:

([flag=romania-1948])
Russia / USSR
Now another one with two. First is the state flag of the Russian Empire, used from 1858 to 1896. Second is the flag of the Soviet Union, whose basic design was used between 1924 and 1991:

([flag=russia-1858])

([flag=ussr-1924])
South Africa
Two flags here. First is the flag used by the Union of South Africa, upon its independence in 1910. Second is the flag that replaced it in 1928, and remained in use until the end of apartheid in 1994:

([flag=south-africa-1910])

([flag=south-africa-1928])
South Vietnam
Just the one here too. It was in use between the country's establishment in 1955, and the Fall of Saigon in 1975:

([flag=south-vietnam-1955])
South Sudan
One flag here. It's the initial post-independence flag, used between 2011 and 2023 (similar to the current one, but with a darker shade of blue in the triangle):

([flag=south-sudan-2011])
South Yemen
Just one flag here. It was used for the duration of the state's existence, between 1967 and 1990:

([flag=south-yemen-1967])
Spain
Two flags here. First is the flag of the Second Spanish Republic, used between 1931 and 1939. Second is the flag introduced under Franco in 1945, and used until 1977:

([flag=spain-1931])

([flag=spain-1945])
Syria
Just one flag here. This was used between 1958 and 1961 (when Syria briefly merged with Egypt under the 'United Arab Republic' name), and subsequently used by the Assad regime from 1980 until 2024:

([flag=syria-1958])
Turkey / Ottoman Empire
One flag here. This was used by the Ottoman Empire from the mid-19th century until 1923 (and it's similar to the modern Turkish flag, with a bigger star and moon):

([flag=ottoman-empire-1850])
United States
Only one here. Various 13-star flags were used between 1777 and 1795, and the one I've gone with is the most recognisable one, popularly known as the "Betsy Ross flag":

([flag=usa-1776])
Yugoslavia
Two here. First, we have the flag of the Socialist Federal Republic of Yugoslavia, used between 1946 and 1992. Next is the flag of the Federal Republic of Yugoslavia, used from 1992 until the dissolution of the union in 2006:

([flag=yugoslavia-1946])

([flag=yugoslavia-1992])
To repeat: these flags have been posted
only for use in historical contexts (i.e. when discussing the countries themselves, or individuals or groups connected with those countries, at the time when these flags were in use). However, if you do just want to have historical discussions which involve these former countries and regimes, then go right ahead

.