IP Guide - Look up IP addresses, networks, and ASNs
GRC Port Scan - GRC Internet Security Port Scanner. Tests for open ports on your external IP address.
whatismyip.cc - External IP Address lookup tool with option to scan the external IP address.
ShowIP - ShowIP displays the IP address(es) of the current page in the status bar.
What is My IP Address - Open Source Website To Get Your IPs Address By WebRTC
TrueIP - TrueIP is a small program that runs in the system tray, monitoring your IP address(es).