CTAN

CTAN (Comprehensive TeX Archive Network) is an online collection of open source LaTeX-related files and software (including Beamer). In other words, this network is a LaTeX-only GitHub.
Location.
CTAN is based in the United States, United Kingdom and Germany. They also have several mirror sites (certified clones). Mirror sites are needed in order to avoid access concentration. This effort helps the users to download files without fatal delay.
Similar projects.
CPAN (Comprehensive Perl Archive Network) is the Perl version of CTAN. In the field of statistics, CRAN (Comprehensive R Archive Network) is frequently used.