Lampo - Mutual interests networking app
Glympse - Glympse is the easy way to safely share your location in realtime. No sign-up needed.
Cal.com - Cal.com (formerly Calendso) is the open source Calendly alternative.
Zenly - Zenly is a GPS tracker to locate your friends in realtime.
Wildcard - Discover, connect and meet people at communities
OwnTracks - Cross-platform location sharing