This is a list of modified country tags in the game that aren't in the country tags file as well as separatist states. The reason this thread exists is because there are a lot of countries that you can't find in the mod files unlike the proprietary ones that have new country tags (for anyone wondering why there are only modified country tags).
*only 2019 scenario
**countries in brackets after the tag are the ones from the base game which are modified, if there's none it's simply a new tag


#Africa#
Senegal = JOL (Jolof)
Guinea-Bissau = KBU (Kaabu)
Ghana = ASH (Ashanti)
Burkina Faso = MSI (Mossi)
Togo = OYO (Oyo)
Benin (Dahomey) = DAH (DAH)
♥♥♥♥♥ = AIR (Air)
Nigeria = SOK (Sokoto)
Chad = KBO (Kanem Bornu)
Somalia = MJE (Majeerteen)
Somaliland = WAR (Warsangali)
Eritrea = MED (Medri Bahri)
Kel Ahaggar = TMB (Timbuktu)
Botsuana = BTS (Betsimisaraka)
Zimbabwe = ZIM (Mutapa)
Malawi = MRA (Maravi)
Burundi = BUU (Burundi)
Jubaland = AJU (Ajuuran)
Puntland = MJE (Majeerteen)

#Asia#
Kharabakh = MLK (Karabakh)
Azerbaijan = SRV (Shirvan)
Turkmenistan = KHI (Khiva)
Uzbekistan = SHY (Uzbek)
Myanmar (Burma) = TAU (Taungu)
Luang Prabang = LUA (Luang Prabang)
Cambodia = KHM (Khmer)
Democratic Republic of Vietnam = ANN (Annam)
Malaysia = MLC (Malacca)
Kokang = KOK (Ferghana)
Kotte = CEY (Kotte)
Bangladesh = BNG (Bengal)
Brunei = BEI (Brunei)
Laos = LUA (Luang Prabang)
Bangsamoro = SUL (Sulu)

#Americas#
Chiapas = ITZ (Itza)

#Europe#
Belarus = PLT (Polotsk)
Latvia = LVA (Livonia)

##Separatist States (countries not released in Present Day)##

##Angloamerica##
#Canada#
Acadia (New Brunswick) = ACD
Nova Scotia = NWS
Québec = QUE
Newfoundland and Labrador = NWL
Inuit = INT
Saskatchewan = STC
Alberta = ABR
Cascadia = CSD
#United States#
Navajo = NAH
California = CAL
Texas = TEX
Confederate States = CSA
New England = NWG
Hawaii = HWI
Alaska = ALK
##Latin America##
#Mexico#
Chiapas (independent) = ITZ
Yucatán = XIU
Zulia = ZLA
#Brazil#
Pernambuco = PMC
Rio de Janeiro = RDJ
Rio Grande = RGD
#Bolivia#
Santa Cruz = STZ
#Nicaragua#
Mosquito = MSK
#Argentina#
Mapuche (La Plata)= MPC (Chile/Argentina)
#Africa#
#Zaire#
(Bas-)Kongo = KON
Gabon / RoK
Loango = LOA
#Mali#
Azawad = AZW
#Sudan#
Darfur = DAR
East Sudan = BEJ
#South Africa#
Volkstaat = VLK
Zululand = ZUL
#Nigeria#
Biafra = BIA
#Democratic Republic of the Congo#
Katanga = LUB
Kongo = KON
#Morocco#
Rif = RIF
#Algeria#
Kabyla = KBA
#Ethiopia#
Oromia = JIM
Sidama = KAF
Afaria = AFA
##Asia##
#Yemen#
South Yemen = SYM
Mahra = MHR
Hadramut = HDR
#Turkey#
Turcomania = TRC
Bohtan (Turkish Kurdistan) = BHT
Lazica = LAZ
#Iran#
Mahabad = MHB
Ardalan (Iranian Kurdistan) = ARD
Luristan = LRI
Al-Ahwaz = MSY
Qashqaistan = QSH
Mazandaran = TAB
Azerbaijani cores on Iran (Iranian Azerbaijan)
(Iranian) Baluchistan = BAL
#Iraq#
North Iraq (Iraqi Kurdistan)= IKD
Assyria = ASY
#Syria#
Rojava = ROJ
Jabal Druze = JBD
Islamic State = ISL
#Uzbekistan#
Karakalpakstan = KPK
#Afghanistan#
Badakshan = BDK
Hazarajat = HZR
#China#
Manchuria = MCH
Shanxi = SHX
Xibei San Ma = XSM
Sichuan = SCH
Guangxi = NGX
Yunnan = CDL
Tibet = TIB
East Turkestan = KAS
#India#
Khalistan = PUN
Jangladesh = JAN
Jodhpur = JDH
Jaisalmer = JSL
Udaipur = UDP
Hadoti = HAD
Gwalior = GWA
Bundelkhand = BND
Bhopal = BHO
Baroda = BDA
Kutch = KAT
Junagarh = JGD
Garhwal = GHR
Hyderabad = DEC
Marathas = MAR
Bastar = BST
DRV = Dravida
Orissa = ORI
Koch = KMT
Assam (Nagaland) = NGL
Manipur = MLB
Tripura = TPR
Kashmir = KSH
#Pakistan#
Sindhuesh = SND
Bahawalpur = BHW
Chitral = CTR
(Pakistani) Balochistan = BAL
#Myanmar (Burma)#
Shan = SST
Rohingya = ARK
Zo Asia = TSI
Kachinland = KCN
Mon = PEG
Wa = WAS
Kokang = KOK
#Thailand#
Pattani = PAT
#Malaysia#
Sabah = SBH
Sarawak = SRW
#Indonesia#
West Papua = WPA
South Maluku = SML
Minahasa = MNH
Madura = MDR
Borneo = KBR
Riau = RIA
Aceh = ATJ
#Japan#
Ryukyu (Okinawa) = RYU
Ainu (Hokkaido) = ANU
#Sri Lanka#
Tamil Eelam = JFN
##Oceania##
#Papua New Guinea#
Bougainville = BGV
#New Zealand#
Maori = MOI
##Europe##
#Spain#
Galicia = GAL
Aragon = ARA
Castile = CAS
Andalusia = ADU
Murcia = MRC
Léon = LON
Asturias = ASU
Cantabria = CNT
Vasconia (Basque Country) = NAV
Catalonia = CAT
Baleares = MJO
Extremadura = EXT
Valencia = VAL
Canaria = CNR
#Greece#
Crete = CRT
#Italy#
Arpitania = APN
Piedmont = PIE
Liguria = GEN
Tuscany = TUS
Naples (Southern Italy) = NAP
Romagna = FER
Venice = VEN
Friuli = AQU
Trieste = TST
Lombardy = MLO
Sicily = SIC
Sardinia = SAR
#France#
Provence = PRO
Nice = NCE
Occitania = TOU
Corsica = COR
Burgundy = BUR
Alsace = ALS
Lorraine = LOR
Normandy = NRM
Brittany = BRI
New Caledonia = NCL
#Belgium#
Flanders = FLA
Wallonia = HAI
#Netherlands#
Friesland = FRI
#Great Britain#
Gibraltar = GIB
Cornwall = CRN
England = ENG
Wales = WLS
Mann = KOI
Ulster (Northern Ireland) = ULS
Scotland = SCO
Guernsey = GRS
#Sweden#
Scania = SCN
Laponia = SMI
#Denmark#
Bornholm = GOT
#Poland#
Ruthenia = RUT
Lusatia = LUS
Kashubia = KSB
Silesia = SIL
#Germany#
Lusatia = LUS
Pomerania = POM
Schleswig-Holstein = SLW
Franconia = ANS
Swabia = WUR
Rhineland = RVA
Bavaria = BAV
#Serbia#
Vojvodina = VOJ
Sanjak = SNJ
#Bosnia and Herzegovina#
Srpska = RPS
Liberland = LBL
#Croatia#
Istria = IST
#Romania#
Transylvania = TRA
Székelyland = SZE
#Moldovia#
Gagauzia = GGZ
#Bulgaria#
Vidin = VID
#Macedonia#
Illirda = ILR
#Albania#
Epirus = EPI
#Ukraine#
Luhansk = LHS
Donetsk = DTS
#Latvia#
Latgalia = LTG
Courland = KUR
#Finland#
Aland = ALD
#Russia#
Karelia = KRL
Chuvashia = CVS
Tatarstan = KAZ
Udmurtia = PRM
Bashkiria = BSH
Siberia = SIB
Kalmyk = KLM
Kuban = KBN
Avaria = AVR
Chechnya = CCY
Circassia = CIR
Karachay-Balkaria = KBL
Dagestan = GAZ