Frysbe - Frysbe: Make global friends at random and the fling app comes up with features to send messages to strangers from every corner of the world to expand your social circle.
Founders Nation - Find or become a startup cofounder
PenPal World - Connect with people all over the world
CoFoundersLab - Meet 250,000+ entrepreneurs online
Unbordered - Unbordered app comes up with features to help you in finding the perfect language practice and exchange partners so you can practice foreign languages right through your mobile phone.
Findnlink - Find people to work with on your ideas.