Wikipedia:GccTLD

gccTLD or Generic Country Code Top Level Domain refers to certain country code TLDs (ccTLDs) which Google considers to be more like traditional generic TLDs (gTLDs) rather than "country" targeted ones, and treats them accordingly for purposes of search engine optimization and indexing.

Some ccTLDs that are considered to be gccTLDs by Google include:
 * .ad
 * .as
 * .bz
 * .cc
 * .cd
 * .co
 * .dj
 * .fm
 * .io
 * .la
 * .me
 * .ms
 * .nu
 * .sc
 * .sr
 * .su
 * .tv
 * .tk
 * .ws

This list can be found on Google's website.

DotGov claims that “while many TLDs are generic, meaning anyone can obtain a domain name, .gov is a sponsored TLD, where the US Government acts as the sponsor for other US-based government organizations. These organizations are the only ones that can obtain a .gov domain.”