i can:

• name all 196 countries and their flags
• name all 50 us states, their flags, and their capitals

i've linked some resources to help you do the same :)

naming all 196 countries

(note: the information in this section pertains to the jetpunk countries of the world quiz)

you can memorize the name of every country by using this song, with some additional notes down below (the list of countries in the song differs slightly from the countries recognized on the jetpunk quiz):

here are the promised notes:

• the song mentions all 193 UN member states + the 2 UN observer states (Vatican City and Palestine). this differs from jetpunk which recognizes the same 193 UN members + the UN observer of Vatican City (but not Palestine) + 2 countries that are neither UN members nor observers (Kosovo and Taiwan). therefore, for this song to be accurate to the jetpunk quiz, we have to make a few modifications.
• the first modification is adding Taiwan into the song, and we'll do this by modifying the line "Burundi, Lesotho, then Malawi, Togo, the DRC and South Sudan". the DRC stands for the Democratic Republic of the Congo; however, later in the song the Republic of the Congo (a different country) is mentioned as just "Congo", and typing "Congo" into the jetpunk quiz gives you both the Congos so mentioning the DRC here is unnecessary. we can replace "the DRC" with "the ROC", which stands for the Republic of China, the official name of Taiwan (typing in "ROC" is also accepted for Taiwan on jetpunk).
  
• the second modification is adding Kosovo while removing Palestine by modifying the line "Monaco, Liechtenstein, Malta, and Palestine, Fiji, Australia, Sudan!" this time, we're simply going to replace Palestine with Kosovo. unfortunately now part of the verse doesn't rhyme but oh well
  

disclaimer: i am not trying to make any political statements about which countries i do/do not recognize by modifying the song lyrics. i am simply making the lyrics accurate to jetpunk's standards because this guide is intended to help people with the jetpunk countries quiz.

here are the lyrics, modified:

United States, Canada, Mexico, Panama, Haiti, Jamaica, Peru,
Republic Dominican, Cuba, Dominica, then there's El Salvador, too.
St. Lucia, Colombia, Venezuela, Honduras, Guyana, and still,
Guatemala, Bolivia, then Argentina, and Ecuador, Chile, Brazil.
Costa Rica, Belize, Antigua and Barbuda, Trinidad and Tobago, Grenada,
Paraguay, Uruguay, Suriname, Barbados, The Bahamas, Nicaragua.

Norway, and Sweden, and Iceland, and Finland, and Germany, the UAE,
Switzerland, Austria, Czechia, Slovakia, Italy, Turkey, and Greece.
Poland, Romania, Georgia, Albania, Ireland, Russia, Oman,
Bulgaria, Saudi Arabia, Hungary, Cyprus, Iraq, and Iran.
There's Syria, Lebanon, Israel, Jordan, then Yemen, Kuwait, and Bahrain,
The Netherlands, Luxembourg, Belgium, and Portugal, France, UK, Denmark, and Spain.

India, Pakistan, Myanmar, Afghanistan, Thailand, Nepal, and Bhutan,
Bangladesh, Cambodia and both the Koreas and China, Malaysia, Japan.
Mongolia, Laos, Singapore, Indonesia, the Philippines and Tuvalu,
Sri Lanka, The Seychelles, Vietnam and New Zealand, Slovenia, Vanuatu.
Tunisia, Morocco, Uganda, Angola, Zimbabwe, Djibouti, Botswana,
Eswatini, The Gambia, Mozambique, Zambia, Guinea, Algeria, Ghana.

Burundi, Lesotho, then Malawi, Togo, the ROC and South Sudan,
Niger, Nigeria, Chad, and Liberia, Egypt, Benin, and Gabon.
Tanzania, Somalia, Kenya, and Mali, Sierra Leone, and Samoa,
Nauru, Namibia, Senegal, Libya, Cameroon, Congo, Moldova.
Ethiopia, Guinea-Bissau, Madagascar, Rwanda, Burkina Faso,
Sao Tome and Principe, Tonga, Armenia,
Then Mauritania and Lithuania,
Monaco, Liechtenstein, Malta and Kosovo, Fiji, Australia, Sudan!

(But wait, there's more!)

Montenegro and Bosnia/Herzegovina, then Timor-Leste, Turkmenistan,
South Africa, Vatican City and Latvia, Belarus, Azerbaijan,
Mauritius, Uzbekistan, Brunei and Kazakhstan, the Marshall Islands and now,
Kyrgyzstan, then there's Tajikistan, then Eritrea, Qatar and Palau!
Equatorial Guinea and Papua New Guinea, St Vincent and the Grenadines,

The CAR, Serbia, St Kitts and Nevis,

Ukraine and Estonia, North Macedonia,

Then San Marino, Andorra, Comoros, Micronesia, Kiribati and Croatia, Cote d'Ivoire, Cabo Verde, the Solomon Islands, Maldives!

now all you have to do is memorize the song! oh wait there's one more important thing: type-ins

• type-ins are things that you can type on the jetpunk quiz in place of the country's common name. for example, we saw earlier that we could type "ROC" in place of Taiwan, so ROC is a type-in for Taiwan. (btw jetpunk is not case sensitive, which means that it doesn't matter which letters are capital and which are lowercase)
• here is a list i created that has the shortest possible type-ins for every country on the quiz. one type-in that i would definitely learn is DR for Dominican Republic because 1) it's much shorter, 2) the song mentions the country as "Republic Dominican", which isn't accepted by jetpunk and 3) by typing the "Dominica" part of "Dominican Republic", jetpunk will automatically assume that you meant to type the separate country of Dominica so you will have to type "Dominican Republic" again. (also common country abbreviations like USA for the United States, UK for the United Kingdom, etc. are pretty much all accepted, i would recommend scrolling through the type-ins sheet to see what else is accepted)
  

that's all that you need! good luck :D