The CTAN catalogue
Most (La)TeX package code is distributed via CTAN, which holds 1000s of contributed bundles. To enable users to find material, CTAN offers a “Browse CTAN” area, with links to the list of packages, to a list of “topics” (with packages that match each topic), and to a list of authors (with their packages).
General web searches for the same information often suffer from the fact that CTAN is a mirror network: different machines around the world hold the same files, so repeated results can appear in search engine results. The CTAN catalogue is therefore the recommended way of finding material.
Notably, if you know the name of the package you are interested in, it is very likely that the correct CTAN location will be
Source: The CTAN catalogue