CellID Finder - Find a cell phone location using LAC/CellID, GSM BTS coordinates
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.
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!
Cell Signal Monitor - Cell Signal Monitor is an advanced network monitor that helps you to watch the state of cellular network by gathering data about cell towers. The app supports GSM, UMTS and LTE networks. There is a Free edition with adds.
wigle.net - WiGLE (Wireless Geographic Logging Engine)
Fastah 4G Finder - Fastah 4G Finder app contains features through which you can access a color map to get an idea about the speed of the internet on your current network.