OpenSignal - Mobile analytics and insights on wireless connectivity from Opensignal, the independent global standard for understanding the true state of the world's mobile network.
WiFi Map - A crowdsourced list of routers and passwords
OpenCellID - OpenCelliD is the largest Open Database of Cell Towers & their locations. You can geolocate IoT & Mobile devices without GPS, explore Mobile Operator coverage and more!
Café Wifi Search 🔍 - Find great cafés to work from, worldwide.
wigle.net - WiGLE (Wireless Geographic Logging Engine)
Instabridge - Crowdsourced free wifi (now on Android)