Wi-Fi Guard
Free way to block unauthorized devices on your wifi
5 Alternatives To Wi-Fi Guard
LocationAPI
Instantly locate any device w/ WiFi, celltowers & IP address
NetSpot
NetSpot is a free app for wireless site surveys, Wi-Fi analysis, and troubleshooting
WiFire
Automatically connect to free Wi-Fi around you
WifiMapper
Find free WiFi anywhere in the world
WifiMask
Protect your Wi-Fi connection and unblock content