iso3166-2 topic
standards
A collection of standards as PHP Enums: ISO3166, ISO4217, ISO639...
ISO-3166-Countries-with-Regional-Codes
ISO 3166-1 country lists merged with their UN Geoscheme regional codes in ready-to-use JSON, XML, CSV data sets
countries
Countries - ISO-639, ISO-3166 countries codes with subdivisions and names, ISO-4217 currency designators, ITU-T E.164 IDD phone codes, countries capitals, UN M.49 codes, IANA ccTLD countries domains,...
php-isocodes
:star: PHP library providing ISO codes with localization: country (ISO 3166-1), subdivision (ISO 3166-2), language (ISO 639-3), currency (ISO 4217) and scripts (ISO 15924)
3166
This is the best source for iso3166 codes you can found. I am sure.
CountryData.Net
An offline crossplatform .NET library for getting Global Country , iso3166 Short-code and Region Data