What is my IP? - Find out what your IP is. Do not hesitate to open wimip.
GRC Port Scan - GRC Internet Security Port Scanner. Tests for open ports on your external IP address.
TrueIP - TrueIP is a small program that runs in the system tray, monitoring your IP address(es).
whatismyip.cc - External IP Address lookup tool with option to scan the external IP address.
Skeebus - Skeebus is a macOS menu bar app that displays your current public IP address
IPv6 test - IPv6-test.