Signal Monitor provides detailed information on your currently used network, regardless whether you are using WLAN or a cellular connection.

In "Mobile Signal":

Network operators, sim operator, network type, network strength in dbm and ASU, data state, data activity, country code of the mobile phone, device ID, phone type, IP address (internal und external), roaming state, etc.

In "WLAN Signal":

WLAN-Name (SSID), BSSID, MAC address, maximum WLAN speed, IP address, external IP address, net capability, net channel, subnet mask, Gateway IP address, DHCP server address, DNS1 and DNS2 address, etc.

Credits

The app icon is available on https://www.iconfinder.com/icons/483467/communication_feed_network_rss_wireless_icon#size=512