Which Protocols are used for PING?

Question

Okay, I know that the answer to this question is ICMP - all my textbooks are saying so, the Internet is saying so, everyone is saying so... except for my TA. According to this T

Answer 1

The usual command line ping tool uses ICMP Echo, but it's true that other protocols can also be used, and they're useful in debugging different kinds of network problems.

I can remember at least arping (for testing ARP requests) and tcping (which tries to establish a TCP connection and immediately closes it, it can be used to check if traffic reaches a certain port on a host) off the top of my head, but I'm sure there are others aswell.