Guide to how this pack works:

You MUST download CIT Resewn in order to use this pack. As of 30/12/2023, CIT Resewn is a Fabric mod and works for Minecraft 1.20.1 at the Latest. It is not updated to work for any version higher. Optifine or any other "CIT" pack might also work, but I haven't tested.

This pack adds Two types of Flags: Waving and Hanging.
• Waving Flags are obtained by renaming a (usually White) Banner.
• Hanging Flags are obtained by renaming (usually White) Wool.

Most Flags are indeed White Banners or Wool, but there are some exceptions:
• When Flags have an alternate form, the alternate form is a renamed Black Banner/Wool.
• Colored Flags are renamed versions of their respective colored block. For example, if you want a Light Blue Hanging Flag, it would be renamed Light Blue Wool.

List of Flags:
(Remember, rename BANNERS for Waving Flags, and WOOL for Hanging Flags!)

Nations (de jure and de facto), Regions, and People:

abkhazia|apsny
afghanistan|afġānistān|afghānistān
åland|aland|ahvenanmaa
albania|shqipëria|shqypnia|shqipnia|alvanía|arbinishii|albanija (This has an ALTERNATE Flag, rename Black Banner)
algeria|al-jazāʾir|al-dzāyīr|dzayer|algérie
antarctica
appalachia
arapaho|hinono'eino|inun-ina
argentina
armenia|hayastan
assyria|ʾāthor
australia
australian aboriginal
austria|österreich
barbados|ichirouganaim|bim|bimshire
basque country|euskal herria|país vasco|pays basque
belarus|biełaruś|belorussiya
belgium|belgië|belgique|belgien
belize|bileez
botswana
brazil|brasil
brittany|breizh|bretagne|bertaèyn
bulgaria|bǎlgariya
burma|bama
cabo verde|cape verde
california
canada
cascadia
catalonia|catalunya|cataluña|catalonha
cherokee|tsalagi|aniyvwiyaʔi|anigiduwagi|cherokee nation|tsalagihi ayeli|tsalagiyehli
cheyenne|tsitsistas|northern cheyenne|notameohmésêhese|notameohmésėhétaneo'o
chile
colombia
cornwall|kernow
costa rica
côte d'ivoire
croatia|hrvatska
cuba|erekusú
cyprus|kypros
czechia|česko
denmark|danmark
dominica|wai‘tu kubuli|dominique|dominik
dominican republic|república dominicana
ecuador|ikwayur|ekuatur
england
estonia|eesti
faroe islands|føroyar|færøerne
finland|suomi
france
georgia|sakartvelo
germany|deutschland
ghana|gaana|gana
greece|elláda
greenland|kalaallit nunaat|grønland
guernsey|guernési|guernesey
guyana
hawai'i|hawaii
hong kong|hēunggóng|xiānggǎng
hungary|magyarország
iceland|ísland
india|bhārat|bhārata|bhāratam|bharot|bharôt|bhārot|bhārôt|hindōstān|hindustān|indiyā|intiyā|pāratam|siñôt
indonesia
iran|irân
ireland|éire
iroquois|haudenosaunee
isle of man|mannin
israel|yisrāʾēl|ʾisrāʾīl (This has an ALTERNATE Flag, rename Black Banner)
italy|italia
jamaica|jumieka
japan|nihon|nippon
jersey|jèrri
kurdistan
larrakia
latvia|latvija|latveja|lețmō
lesotho
lithuania|lietuva
luxembourg|lëtzebuerg|luxemburg
macau|oumún|àomén
malta
maori|māori
mapuche
mauritius|maurice|moris
mer island|murray island|maer island
mexico|méxico|mēxihco (This has an ALTERNATE Flag, rename Black Banner)
micronesia
mi'kmaq|mi'gmaq|lnu|miꞌkmaw|miꞌgmaw|grand council|santé mawiómi
monaco|mùnegu
mongolia|mongol uls
montenegro|crna gora|mali i zi (This has an ALTERNATE Flag, rename Black Banner)
namibia|namibië|namibiab
nauru|naoero
navajo|diné|navajo nation|naabeehó diné biyaad|naabeehó bináhásdzo
netherlands|nederland|nederlân
new england
new zealand|aotearoa
north macedonia
norway|norge|noreg|norga|vuodna|nöörje
palau|belau
palestine|filasṭīn
panama|panamá
philippines|pilipinas
poland|polska
portugal
rapa nui|easter island|isla de pascua
romani|romany|rromani|roma
romania|românia
russia|rossiya
saint lucia|sent lisi|sainte-lucie
saint vincent and the grenadines
samoa|sāmoa
sápmi|sapmi|sábme|saepmie|sámi|sami|saami
scotland|alba
seychelles|sesel
sioux|očhéthi šakówiŋ|pine ridge|wazí aháŋhaŋ oyáŋke
slovakia|slovensko (This has an ALTERNATE Flag, rename Black Banner)
slovenia|slovenija
somaliland|soomaaliland|ṣūmālīlānd
south africa|suid-afrika|iningizimu afrika|umzantsi afrika|afrika-borwa|afrika borwa|aforika borwa|afurika tshipembe|afrika dzonga|iningizimu afrika|isewula afrika
south korea|hanguk
spain|españa|espanya|espainia|espanha (This has an ALTERNATE Flag, rename Black Banner)
sweden|sverige
switzerland|schweiz|suisse|svizzera|svizra
syria|sūriyā
taiwan|táiwān
tamazgha|tamazɣa|berber|amazigh|imazighen|imaziɣen|amaziɣ
the bahamas
tibet|poi|xīzàng
timor-leste|timór-leste|east timor
tiwi|tiwi islands|tunuvivi|ratuati irara
tonga
torres strait islander
trinidad and tobago
ukraine|ukrajina
united kingdom|y deyrnas unedig|unitit kinrick|rìoghachd aonaichte|ríocht aontaithe|an rywvaneth unys
united states|estados unidos
uruguay
venezuela
wales|cymru
west papau|papua barat
western sahara|sahrawi republic|república saharaui|sahrawi|ṣaḥrāwī

Organizations, Fictional, Misc.:

avali|avali illuminate
ceres
council of europe|european union|europe
earth
jupiter
mars
maw
mercury
moon
neptune
olympic
paw
pirate|jolly roger
planet x
pluto
saturn
sergal|shigu|sieg
united nations
uranus
venus

Pride:

abrosexual|abrosexual pride
agender|agender pride
ally|ally pride (This has an ALTERNATE Flag, rename Black Banner/Wool)
androgyne|androgyne pride
androgynous|androgynous pride
aromantic|aromantic pride|aro|aro pride
aromantic asexual|aromantic asexual pride|aroace|aroace pride
asexual|asexual pride|ace|ace pride
bigender|bigender pride
bisexual|bisexual pride|bi|bi pride
demigender|demigender pride
demiromantic|demiromantic pride
demisexual|demisexual pride
femboy|femboy pride
genderfluid|genderfluid pride
genderqueer|genderqueer pride
intersex|intersex pride
lesbian|lesbian pride|gay women|gay women pride
lgbt|lgbt pride|lgbt+|lgbt+ pride|lgbtq|lgbtq pride|lgbtq+|lgbtq+ pride|lgbtqia|lgbtqia pride|lgbtqia+|lgbtqia+ pride|gay|gay pride (This has an ALTERNATE Flag, rename Black Banner/Wool)
neutrois|neutrois pride
non-binary|non-binary pride|nonbinary|nonbinary pride|enby|enby pride
pansexual|pansexual pride (This has an ALTERNATE Flag, rename Black Banner/Wool)
polyamorous|polyamorous pride
polysexual|polysexual pride
progress|progress pride (This has an ALTERNATE Flag, rename Black Banner/Wool)
queer|queer pride
tomboy|tomboy pride
transgender|transgender pride|trans|trans pride
two-spirit|two-spirit pride (This has an ALTERNATE Flag, rename Black Banner/Wool)
vincian|vincian pride|gay men|gay men pride

Colors:

Black Flag (Rename Black Banner/Wool)
Black Pennant (Rename Black Banner/Wool)
Blue Flag (Rename Blue Banner/Wool)
Blue Pennant (Rename Blue Banner/Wool)
Brown Flag (Rename Brown Banner/Wool)
Brown Pennant (Rename Brown Banner/Wool)
Cyan Flag (Rename Cyan Banner/Wool)
Cyan Pennant (Rename Cyan Banner/Wool)
Gray Flag (Rename Gray Banner/Wool)
Gray Pennant (Rename Gray Banner/Wool)
Green Flag (Rename Green Banner/Wool)
Green Pennant (Rename Green Banner/Wool)
Light Blue Flag (Rename Light Blue Banner/Wool)
Light Blue Pennant (Rename Light Blue Banner/Wool)
Light Gray Flag (Rename Light Gray Banner/Wool)
Light Gray Pennant (Rename Light Gray Banner/Wool)
Lime Flag (Rename Lime Banner/Wool)
Lime Pennant (Rename Lime Banner/Wool)
Magenta Flag (Rename Magenta Banner/Wool)
Magenta Pennant (Rename Magenta Banner/Wool)
Orange Flag (Rename Orange Banner/Wool)
Orange Pennant (Rename Orange Banner/Wool)
Pink Flag (Rename Pink Banner/Wool)
Pink Pennant (Rename Pink Banner/Wool)
Purple Flag (Rename Purple Banner/Wool)
Purple Pennant (Rename Purple Banner/Wool)
Red Flag (Rename Red Banner/Wool)
Red Pennant (Rename Red Banner/Wool)
White Flag (Rename White Banner/Wool)
White Pennant (Rename White Banner/Wool)
Yellow Flag (Rename Yellow Banner/Wool)
Yellow Pennant (Rename Yellow Banner/Wool)

I did my best to credit all the original flag designers in each of their respective .properties files. The pixel art of all these flags is done by me!