Wikipedia's list of social networking sites lists a lot of entries in the social networking scene.

Commercial

Facebook

Free social network does not only mean that it is free of charge but refers also to user freedom and freedom from ads and tracking.

PodUpTi.me is a place to discover many instances of diaspora*, Friendica, Hubzilla and Socialhome out there.

The Diaspora* social network is a distributed social network that runs on the extremely fine quality Diaspora* software.

Hubzilla