The United Kingdom does not have so much a national anthem as a royal one. "God Save the Queen/King" does not mention the country, the region, the people or anything. It's entirely about her (or him).
In the Dutch national anthem's first verse William of Nassau opens boasting about being German and ends pledging loyalty to the King of Spain.
The Swedish one doesn't mention Sweden, only "the north".
Though it might be an indirect reference to Sweden through that. When the anthem was composed, Sweden claimed to be the north, as the king of Sweden was also king of Norway and claimed all of Finland as a "true" part of Sweden.
It was an indirect reference, but not in that way — it was written at a time of high Scandinavism, when Norden/Scandinavia coming together as one was a popular idea. Sweden is, of course, a part of the North (upper-case important: Norden is a place-name, not a direction-descriptor). In other words, the Swedish National Anthem is fairly national (it is extolling the virtues of the Nation as a place to live) — but for the Scandinavian nation that never became a nation-state rather than the Kingdom of Sweden proper.
Until 1944 the Soviet Union's national anthem was "The Internationale" and it was originally written to be sung to "La Marseillaise". It's extremely fortunate that the Russian-language version of "The Internationale"—which is notoriously difficult to translate—actually works pretty well (unlike the English and Chinese translations), or else things would have been rather awkward for about 25 years.
The East German anthem had lyrics, but they weren't sung because they controversially referred to a united Germany, not the DDR.
Israel's "The Hope" takes its lyrics from a 19th-century poem. Consequently, the poem only expresses the "hope" for Zion, and talks about looking to the holy land from abroad. The music, for its part, comes from an Italian folk song via Romania.
The Palestinian anthem, "Mawtini", also comes from a pre-existing poem. Its lyrics are vague enough to serve as the new anthem of Iraq as well.
The Deutschlandlied was written while the author was on holiday on a British island (Heligoland), although the island's German now.
Not an actual national anthem, but "The Battle Hymn of the Republic" is considered an American patriotic standard and is associated with the Union side in The American Civil War. However, the only thing the lyrics actually talk about is Jesus Christ and the Second Coming. The unspoken subtext is, "God is on our side, so screw you slave-holding Confederates!"
While most national anthems are in the standard major scale, there are a number of exceptions.
"Hatikvah" (Israel), "Mila Rodino" (Bulgaria) and "Meniñ Qazaqstanım" (Kazakhstan) are in a minor scale.
"Kimigayo" (Japan), "Ee Mungu Nguvu Yetu" (Kenya) and "Sayaun Thunga Phool Ka" (Nepal) use pentatonic scales.
"Ey Iran" (Iran, unofficial) uses the Phrygian mode (known in Middle Eastern music as a variety of maqam kurd).
The national anthem of South Africa is the only national anthem of the world that does not end on the same key on which it starts, as that one is an amalgamation of the Black nationalistic hymn God Bless Africa and the former (White) anthem The Voice of South Africa, like the Czechslovakia example below.
The anthem of the European Union is Ludwig van Beethoven's Ninth Symphony. The tune was written for the poem "Ode to Joy" by Schiller, which expresses all the liberal international sentiments appropriate to the EU, but the EU doesn't use it and the anthem has no lyrics.
Once upon a time, Franz Josef Haydn wrote a melody for a poem The Austrian King. With those words, the song became the national anthem of Austria-Hungary until it was dissolved in 1918, and Austria got a new one altogether. With a new set of lyrics, the Haydn melody became the Deutschlandlied aka "Deutschland über alles", but this wasn't officially adopted until the Weimar Republic after World War I. After World War II, West Germany kept the song, but only the less controversial third stanza.
Rabindranath Tagore wrote the words and melodies of both India's and Bangladesh's anthems—he was a Hindu Bengali living before the Muslim League (which caused the division of British India into India and Pakistan, which in turn broke up into Pakistan and Bangladesh), so it rather makes sense.
The words to Norway's "Ja, vi elsker dette landet"Translation "Yes, We Love This Country" were written by one of its Nobel-prize winning writers. Its tune was written by his cousin.
The words, but not the tune, of Colombia's anthem were written by Rafael Núñez Moledo, who also wrote Colombia's first constitution.
Both the Japanese and the first Korean national anthems had their music made by Franz Eckert, a German.
Czechslovakia used the first stanza of the Czech anthem, then the second stanza of the Slovak one. When the nation broke up, they just split the anthems, too.
"The Star-Spangled Banner" seems to be based on "The Anacreontic Song", often described as a drinking song. It didn't become the national anthem of the United States until 1931; before then, it was "My Country 'Tis of Thee", which has the same tune as "God Save the King". Surprisingly, the composer of the piece wasn't aware of this.
"The Star-Spangled Banner" is often noted as one of the most difficult, if not the most difficult, of all national anthems to sing. This has everything to do with its roots as a drinking song—"The Anacreontic Song" was used by members of the Anacreontic Society—an artistic Brotherhood of Funny Hats in 18th-century London—to judge how drunk you were. If you could sing it properly, you hadn't had enough yet; if the music failed you, it was time to stop.
Another popular one was "Hail Columbia", which, while very patriotic and speaking of The American Revolutionnote As opposed to the not-all-that-important War of 1812, which is what "The Star-Spangled Banner" refers to, referred to "Columbia," an outdated name by the time an official anthem was to be adopted, not to mention the confusion it could cause with a certain other Latin American nation.
The lyrics to the Japanese "Kimigayo" date from a poem collection from over a thousand years ago, but were not used for an anthem until the 19th century.
The anthem of the People's Republic of China, "March of the Volunteers", was banned in the country for a while after its composer was imprisoned during the Cultural Revolution.
March of the Volunteers is a possibly rare example of composed for a movie before it was adopted as the anthem.
The Republic of China in Taiwan has an anthem in classical literary Chinese; the anthem of the People's Republic of China is in modern vernacular.
The national anthem of the Republic of China could not be played at international events. The national anthem of "Chinese Taipei" you hear at football matches and Olympic medal ceremonies is the National Flag Song, which is used in Taiwan at flag-raising/lowering ceremonies.
"God Save the Queen" is one of the oldest and most influential anthems: World War I Germany, imperial Russia, Switzerland and Hawaii used to use the melody for their own, and Liechtenstein still does. Norway and Sweden use it as a royal but not a national anthem.
The national anthem of Spain has no lyrics. Certain lyrics were used during the Spanish empire, others during the Fascist regime, but those have fallen out of favor and no one has agreed to a replacement.
This is probably due to strong, regional linguistic pride, most particularly from the Catalans and Basques. Galicians are equally proud but less prone to manifesting it.
And this makes it even more jarring when you are watching a sports event and the anthem is played- and you realize that people still don't know it. Even though it has no lyrics to memorize. Even though there is only two verses, each played twice, both relatively short. Regardless, people will still sing them wrong. Wow.
The Canadian national anthem, "O Canada", has two separate sets of lyrics: one in English and one in French. However, the French lyrics are entirely different from the English lyrics when translated; the English lyrics are about being patriotic for Canada, while the French lyrics are about vowing to protect Canada, and contain a fair about of Christian imagery.
There's also an Inuktitut version, as well.
The tune of "Negaraku", Malaysia's national anthem, comes from "La Rosalie", a song by French poet Pierre-Jean de Béranger. This song was played in Seychelles, where Sultan Idris Murshidul’adzam Shah, ruler of the state of Perak from 1887, was exiled for 18 years. He brought the tune back to Perak and adopted it as his state anthem, which was subsequently selected as the nation's anthem 70 years later. However, nobody is sure that the French song truly exists.