Diaspora's still around. Identi.ca (not to be confused with Friendica) became Status.net which is now Pump.io but if you want to try it out you have to visit Ephemeral Me. There's Tent.io which you used to be able to try out at Tent.is but is now Cupcake.io. Diaspora and Tent considered getting together but decided not to. Still with me? Good, because Status.net is now part of GNU Social. There's Feedly which became the Stream Framework with SaaS commercial partner GetStream.io.