wigle.net - WiGLE (Wireless Geographic Logging Engine)
RottenWifi - Rotten WiFi is public wifi and 3G Watchdog.
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!
Mozilla Stumbler - Mozilla Stumbler is an open-source wireless network scanner that collects GPS data for the Mozilla...
CellID Finder - Find a cell phone location using LAC/CellID, GSM BTS coordinates
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.