Social tools is a term which refers to the SocialProfile extension and various other related extensions, most of which depend on the SocialProfile extension.
Many of the social tools were developed by Aaron Wright, Ashish Datta, David Pean, Jeffrey Tierney and Robert Lefkowitz for ArmchairGM. Currently the SocialProfile extension and other related social tools are maintained by Jack Phoenix (the lead maintainer) in collaboration with a few other people, UltrasonicNXT and SamanthaNguyen.
For a complete list of social tools, see Category:Social tools.
The extensions under the social tools umbrella have a dedicated testing environment which is hosted on Wikimedia Cloud VPS, which will almost always be running the most recent commit from the master branch of each social tool extensions. Documentation of the Cloud VPS instance is available on Wikitech.