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.

Wireshark - Wireshark is a network protocol analyzer for Unix and Windows. It lets you capture and interactively browse the traffic running on a computer network.

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!

NetMonster - NetMonster is a networking app by Michal Mrocek that comes up with features to enable you to get detailed information about your current network right on your mobile phone screen.

wigle.net - WiGLE (Wireless Geographic Logging Engine)

Mojo Packets - Wireless Troubleshooting Made Easy