Founders Nation - Find or become a startup cofounder
PenPal World - Connect with people all over the world
CoFoundersLab - Meet 250,000+ entrepreneurs online
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.
Co-founder Question Cards - Questions to ask your co-founder to know each other better.
Yochat - Yochat app enables users to get to know about strangers from a large number of countries from around the world by video chatting with them.