There are a few ways to bulk download all the nation flags of the world in their full names.
--1--
Flagpedia.net offers a free download of all 254 country flags in a single package. The flags are available in vector format, which means they can be scaled without losing quality. The download also includes the full name of each country in English.
--2-- Wikipedia Commons
has a collection of flag images that are free to use for commercial and non-commercial purposes. The images are available in a variety of formats, including PNG, JPEG, and SVG. You can search for flags by country name or by ISO Alpha-2 code.
https://vi.wikipedia.org/wiki/Wikimedia_Commons--3-- GitHub has a repository called hampusborgos/country-flags
that contains accurate renders of all the world's flags in SVG and PNG format. The flags are not under copyright protection since flags are in public domain.
--4-- KAGGLE is a research tool to access various datasets that people have put together for download. It doesn't have a list of the many cities in Mexico that moot has visited (aka mootxico), but there are datasets of country flags.
https://www.kaggle.com/search?q=flags--5-- Data.world
has a dataset called Country flags image database from Wikipedia that contains a list of countries, file names, and URLs to the flag images in tabular format from Wikipedia.
https://docs.data.world/en/98423-find-data-on-data-world.html 
