This is more for fun, but also useful experiment for Nationality Flags with two different approaches.
Countries and all relevant details are served by Football Teams Country API.

Total Countries 212
Flag Single Flag Sprite Name Official Name FIFA ISO3 ISO2 UNI Fifa Association
Afghanistan Islamic Republic of Afghanistan AFG AFG AF 4 Afghanistan Football Federation
Albania Republic of Albania ALB ALB AL 8 Albanian Football Association
Algeria People's Democratic Republic of Algeria ALG DZA DZ 12 Algerian Football Federation
American Samoa ASA Football Federation American Samoa
Andorra Principality of Andorra AND AND AD 20 Andorran Football Federation
Angola Republic of Angola ANG AGO AO 24 Angolan Football Federation
Anguilla AIA Anguilla Football Association
Antigua and Barbuda Antigua and Barbuda ATG ATG AG 28 Antigua and Barbuda Football Association
Argentina Argentine Republic ARG ARG AR 32 Argentine Football Association
Armenia Republic of Armenia ARM ARM AM 51 Football Federation of Armenia
Aruba ARU Aruba Football Federation
Australia Australia AUS AUS AU 36 Football Federation Australia
Austria Republic of Austria AUT AUT AT 40 Austrian Football Association
Azerbaijan Republic of Azerbaijan AZE AZE AZ 31 Association of Football Federations of Azerbaijan
Bahamas Commonwealth of Bahamas BAH BHS BS 44 Bahamas Football Association
Bahrain Kingdom of Bahrain BHR BHR BH 48 Bahrain Football Association
Bangladesh People's Republic of Bangladesh BAN BGD BD 50 Bangladesh Football Federation
Barbados Barbados BRB BRB BB 52 Barbados Football Association
Belarus Republic of Belarus BLR BLR BY 112 Football Federation of Belarus
Belgium Kingdom of Belgium BEL BEL BE 56 Royal Belgian Football Association
Belize Belize BLZ BLZ BZ 84 Football Federation of Belize
Benin Republic of Benin BEN BEN BJ 204 Benin Football Federation
Bermuda BER Bermuda Football Association
Bhutan Kingdom of Bhutan BHU BTN BT 64 Bhutan Football Federation
Bolivia Plurinational State of Bolivia BOL BOL BO 68 Bolivian Football Federation
Bosnia and Herzegovina Bosnia and Herzegovina BIH BIH BA 70 Football Association of Bosnia and Herzegovina
Botswana Republic of Botswana BOT BWA BW 72 Botswana Football Association
Brazil Federative Republic of Brazil BRA BRA BR 76 Brazilian Football Confederation
British Virgin Islands VGB British Virgin Islands Football Association
Brunei Brunei Darussalam BRU BRN BN 96 National Football Association of Brunei Darussalam
Bulgaria Republic of Bulgaria BUL BGR BG 100 Bulgarian Football Union
Burkina Faso Burkina Faso BFA BFA BF 854 Burkinabé Football Federation
Burundi Republic of Burundi BDI BDI BI 108 Football Federation of Burundi
Cambodia Kingdom of Cambodia CAM KHM KH 116 Football Federation of Cambodia
Cameroon Republic of Cameroon CMR CMR CM 120 Cameroonian Football Federation
Canada Canada CAN CAN CA 124 Canadian Soccer Association
Cape Verde Republic of Cabo Verde CPV CPV CV 132 Cape Verdean Football Federation
Cayman Islands CAY Cayman Islands Football Association
Central African Republic Central African Republic CTA CAF CF 140 Central African Football Federation
Chad Republic of Chad CHA TCD TD 148 Chadian Football Federation
Chile Republic of Chile CHI CHL CL 152 Football Federation of Chile
China PR People's Republic of China CHN CHN CN 156 Chinese Football Association
Chinese Taipei TPE Chinese Taipei Football Association
Colombia Republic of Colombia COL COL CO 170 Colombian Football Federation
Comoros Union of Comoros COM COM KM 174 Comoros Football Federation
Congo Republic of Congo CGO COG CG 178 Congolese Football Federation
Cook Islands Cook Islands COK COK CK 184 Cook Islands Football Association
Costa Rica Republic of Costa Rica CRC CRI CR 188 Costa Rican Football Federation
Croatia Republic of Croatia CRO HRV HR 191 Croatian Football Federation
Cuba Republic of Cuba CUB CUB CU 192 Football Association of Cuba
Curaçao CUW Curaçao Football Federation
Cyprus Republic of Cyprus CYP CYP CY 196 Cyprus Football Association
Czech Republic Czech Republic CZE CZE CZ 203 Football Association of the Czech Republic
Denmark Kingdom of Denmark DEN DNK DK 208 Danish Football Union
Djibouti Republic of Djibouti DJI DJI DJ 262 Djiboutian Football Federation
Dominica Commonwealth of Dominica DMA DMA DM 212 Dominica Football Association
Dominican Republic Dominican Republic DOM DOM DO 214 Dominican Football Federation
DR Congo Democratic Republic of Congo COD COD CD 180 Congolese Association Football Federation
Ecuador Republic of Ecuador ECU ECU EC 218 Ecuadorian Football Federation
Egypt Arab Republic of Egypt EGY EGY EG 818 Egyptian Football Association
El Salvador Republic of El Salvador SLV SLV SV 222 Salvadoran Football Federation
England ENG The Football Association
Equatorial Guinea Republic of Equatorial Guinea EQG GNQ GQ 226 Equatoguinean Football Federation
Eritrea State of Eritrea ERI ERI ER 232 Eritrean National Football Federation
Estonia Republic of Estonia EST EST EE 233 Estonian Football Association
Eswatini Kingdom of Eswatini SWZ SWZ SZ 748 Eswatini Football Association
Ethiopia Federal Democratic Republic of Ethiopia ETH ETH ET 231 Ethiopian Football Federation
Faroe Islands Faroe Islands FRO FRO FO 234 Faroe Islands Football Association
Fiji Republic of Fiji FIJ FJI FJ 242 Fiji Football Association
Finland Republic of Finland FIN FIN FI 246 Football Association of Finland
France French Republic FRA FRA FR 250 French Football Federation
Gabon Gabonese Republic GAB GAB GA 266 Gabonese Football Federation
Gambia Republic of Gambia GAM GMB GM 270 Gambia Football Federation
Georgia Georgia GEO GEO GE 268 Georgian Football Federation
Germany Federal Republic of Germany GER DEU DE 276 German Football Association
Ghana Republic of Ghana GHA GHA GH 288 Ghana Football Association
Gibraltar GIB Gibraltar Football Association
Greece Hellenic Republic GRE GRC GR 300 Hellenic Football Federation
Grenada Grenada GRN GRD GD 308 Grenada Football Association
Guam GUM Guam Football Association
Guatemala Republic of Guatemala GUA GTM GT 320 National Football Federation of Guatemala
Guinea Republic of Guinea GUI GIN GN 324 Guinean Football Federation
Guinea-Bissau Republic of Guinea-Bissau GNB GNB GW 624 Football Federation of Guinea-Bissau
Guyana Co-operative Republic of Guyana GUY GUY GY 328 Guyana Football Federation
Haiti Republic of Haiti HAI HTI HT 332 Haitian Football Federation
Honduras Republic of Honduras HON HND HN 340 National Autonomous Federation of Football of Honduras
Hong Kong HKG Hong Kong Football Association
Hungary Hungary HUN HUN HU 348 Hungarian Football Federation
Iceland Republic of Iceland ISL ISL IS 352 Football Association of Iceland
India Republic of India IND IND IN 356 All India Football Federation
Indonesia Republic of Indonesia IDN IDN ID 360 Football Association of Indonesia
Iran Islamic Republic of Iran IRN IRN IR 364 Football Federation Islamic Republic of Iran
Iraq Republic of Iraq IRQ IRQ IQ 368 Iraq Football Association
Israel State of Israel ISR ISR IL 376 Israel Football Association
Italy Republic of Italy ITA ITA IT 380 Italian Football Federation
Ivory Coast Republic of Côte d'Ivoire CIV CIV CI 384 Ivorian Football Federation
Jamaica Jamaica JAM JAM JM 388 Jamaica Football Federation
Japan Japan JPN JPN JP 392 Japan Football Association
Jordan Hashemite Kingdom of Jordan JOR JOR JO 400 Jordan Football Association
Kazakhstan Republic of Kazakhstan KAZ KAZ KZ 398 Football Federation of Kazakhstan
Kenya Republic of Kenya KEN KEN KE 404 Football Kenya Federation
Kosovo KVX Football Federation of Kosovo
Kuwait State of Kuwait KUW KWT KW 414 Kuwait Football Association
Kyrgyzstan Kyrgyz Republic KGZ KGZ KG 417 Football Federation of the Kyrgyz Republic
Laos Lao People's Democratic Republic LAO LAO LA 418 Lao Football Federation
Latvia Republic of Latvia LVA LVA LV 428 Latvian Football Federation
Lebanon Lebanese Republic LBN LBN LB 422 Lebanese Football Association
Lesotho Kingdom of Lesotho LES LSO LS 426 Lesotho Football Association
Liberia Republic of Liberia LBR LBR LR 430 Liberia Football Association
Libya State of Libya LBY LBY LY 434 Libyan Football Federation
Liechtenstein LIE Liechtenstein Football Association
Lithuania Republic of Lithuania LTU LTU LT 440 Lithuanian Football Federation
Luxembourg Grand Duchy of Luxembourg LUX LUX LU 442 Luxembourg Football Federation
Macau MAC Macau Football Association
Madagascar Republic of Madagascar MAD MDG MG 450 Malagasy Football Federation
Malawi Republic of Malawi MWI MWI MW 454 Football Association of Malawi
Malaysia Malaysia MAS MYS MY 458 Football Association of Malaysia
Maldives Republic of Maldives MDV MDV MV 462 Football Association of Maldives
Mali Republic of Mali MLI MLI ML 466 Malian Football Federation
Malta Republic of Malta MLT MLT MT 470 Malta Football Association
Mauritania Islamic Republic of Mauritania MTN MRT MR 478 Football Federation of the Islamic Republic of Mauritania
Mauritius Republic of Mauritius MRI MUS MU 480 Mauritius Football Association
Mexico United Mexican States MEX MEX MX 484 Mexican Football Federation
Moldova Republic of Moldova MDA MDA MD 498 Moldovan Football Federation
Mongolia Mongolia MNG MNG MN 496 Mongolian Football Federation
Montenegro Montenegro MNE MNE ME 499 Football Association of Montenegro
Montserrat MSR Montserrat Football Association
Morocco Kingdom of Morocco MAR MAR MA 504 Royal Moroccan Football Federation
Mozambique Republic of Mozambique MOZ MOZ MZ 508 Mozambican Football Federation
Myanmar Republic of Union of Myanmar MYA MMR MM 104 Myanmar Football Federation
Namibia Republic of Namibia NAM NAM NA 516 Namibia Football Association
Nepal Federal Democratic Republic of Nepal NEP NPL NP 524 All Nepal Football Association
Netherlands Kingdom of Netherlands NED NLD NL 528 Royal Dutch Football Association
New Caledonia NCL New Caledonian Football Federation
New Zealand New Zealand NZL NZL NZ 554 New Zealand Football
Nicaragua Republic of Nicaragua NCA NIC NI 558 Nicaraguan Football Federation
Niger Republic of Niger NIG NER NE 562 Nigerien Football Federation
Nigeria Federal Republic of Nigeria NGA NGA NG 566 Nigeria Football Federation
North Korea Democratic People's Republic of Korea PRK PRK KP 408 DPR Korea Football Association
North Macedonia Republic of North Macedonia MKD MKD MK 807 Football Federation of North Macedonia
Northern Ireland United Kingdom of Great Britain and Northern Ireland NIR GBR GB 826 Irish Football Association
Norway Kingdom of Norway NOR NOR NO 578 Norwegian Football Federation
Oman Sultanate of Oman OMA OMN OM 512 Oman Football Association
Pakistan Islamic Republic of Pakistan PAK PAK PK 586 Pakistan Football Federation
Palestine PLE Palestinian Football Association
Panama Republic of Panama PAN PAN PA 591 Panamanian Football Federation
Papua New Guinea Independent State of Papua New Guinea PNG PNG PG 598 Papua New Guinea Football Association
Paraguay Republic of Paraguay PAR PRY PY 600 Paraguayan Football Association
Peru Republic of Peru PER PER PE 604 Peruvian Football Federation
Philippines Republic of Philippines PHI PHL PH 608 Philippine Football Federation
Poland Republic of Poland POL POL PL 616 Polish Football Association
Portugal Portuguese Republic POR PRT PT 620 Portuguese Football Federation
Puerto Rico PUR Puerto Rican Football Federation
Qatar State of Qatar QAT QAT QA 634 Qatar Football Association
Republic of Ireland Ireland IRL IRL IE 372 Football Association of Ireland
Romania Romania ROU ROU RO 642 Romanian Football Federation
Russia Russian Federation RUS RUS RU 643 Russian Football Union
Rwanda Republic of Rwanda RWA RWA RW 646 Rwandese Association Football Federation
Saint Kitts and Nevis Saint Kitts and Nevis SKN KNA KN 659 St. Kitts and Nevis Football Association
Saint Lucia Saint Lucia LCA LCA LC 662 Saint Lucia Football Association
Saint Vincent and the Grenadines Saint Vincent and Grenadines VIN VCT VC 670 Saint Vincent and the Grenadines Football Federation
Samoa Independent State of Samoa SAM WSM WS 882 Football Federation Samoa
San Marino Republic of San Marino SMR SMR SM 674 San Marino Football Federation
São Tomé and Príncipe Democratic Republic of Sao Tome and Principe STP STP ST 678 São Toméan Football Federation
Saudi Arabia Kingdom of Saudi Arabia KSA SAU SA 682 Saudi Arabian Football Federation
Scotland SCO Scottish Football Association
Senegal Republic of Senegal SEN SEN SN 686 Senegalese Football Federation
Serbia Republic of Serbia SRB SRB RS 688 Football Association of Serbia
Seychelles Republic of Seychelles SEY SYC SC 690 Seychelles Football Federation
Sierra Leone Republic of Sierra Leone SLE SLE SL 694 Sierra Leone Football Association
Singapore Republic of Singapore SIN SGP SG 702 Football Association of Singapore
Slovakia Slovak Republic SVK SVK SK 703 Slovak Football Association
Slovenia Republic of Slovenia SVN SVN SI 705 Football Association of Slovenia
Solomon Islands Solomon Islands SOL SLB SB 90 Solomon Islands Football Federation
Somalia Federal Republic of Somalia SOM SOM SO 706 Somali Football Federation
South Africa Republic of South Africa RSA ZAF ZA 710 South African Football Association
South Korea Republic of Korea KOR KOR KR 410 Korea Football Association
South Sudan Republic of South Sudan SSD SSD SS 728 South Sudan Football Association
Spain Kingdom of Spain ESP ESP ES 724 Royal Spanish Football Federation
Sri Lanka Democratic Socialist Republic of Sri Lanka SRI LKA LK 144 Football Federation of Sri Lanka
Sudan Republic of Sudan SDN SDN SD 736 Sudan Football Association
Suriname Republic of Suriname SUR SUR SR 740 Surinamese Football Association
Sweden Kingdom of Sweden SWE SWE SE 752 Swedish Football Association
Switzerland Swiss Confederation SUI CHE CH 756 Swiss Football Association
Syria Syrian Arab Republic SYR SYR SY 760 Syrian Arab Federation for Football
Tahiti TAH Tahitian Football Federation
Tajikistan Republic of Tajikistan TJK TJK TJ 762 Tajikistan Football Federation
Tanzania United Republic of Tanzania TAN TZA TZ 834 Tanzania Football Federation
Thailand Kingdom of Thailand THA THA TH 764 Football Association of Thailand
Timor-Leste Democratic Republic of Timor-Leste TLS TLS TL 626 East Timor Football Federation
Togo Togolese Republic TOG TGO TG 768 Togolese Football Federation
Tonga Kingdom of Tonga TGA TON TO 776 Tonga Football Association
Trinidad and Tobago Republic of Trinidad and Tobago TRI TTO TT 780 Trinidad and Tobago Football Association
Tunisia Republic of Tunisia TUN TUN TN 788 Tunisian Football Federation
Turkey Republic of Turkey TUR TUR TR 792 Turkish Football Federation
Turkmenistan Turkmenistan TKM TKM TM 795 Football Federation of Turkmenistan
Turks and Caicos Islands TCA Turks and Caicos Islands Football Association
Uganda Republic of Uganda UGA UGA UG 800 Federation of Uganda Football Associations
Ukraine Ukraine UKR UKR UA 804 Ukrainian Association of Football
United Arab Emirates United Arab Emirates UAE ARE AE 784 United Arab Emirates Football Association
United States United States of America USA USA US 840 United States Soccer Federation
Uruguay Eastern Republic of Uruguay URU URY UY 858 Uruguayan Football Association
U.S. Virgin Islands VIR U.S. Virgin Islands Soccer Federation
Uzbekistan Republic of Uzbekistan UZB UZB UZ 860 Uzbekistan Football Association
Vanuatu Republic of Vanuatu VAN VUT VU 548 Vanuatu Football Federation
Venezuela Bolivarian Republic of Venezuela VEN VEN VE 862 Venezuelan Football Federation
Vietnam Socialist Republic of Viet Nam VIE VNM VN 704 Vietnam Football Federation
Wales WAL Football Association of Wales
Yemen Republic of Yemen YEM YEM YE 887 Yemen Football Association
Zambia Republic of Zambia ZAM ZMB ZM 894 Football Association of Zambia
Zimbabwe Republic of Zimbabwe ZIM ZWE ZW 716 Zimbabwe Football Association
United Kingdom United Kingdom of Great Britain and Northern Ireland GBR GBR GB 826 None