If you hold the ESC key for more than 3 seconds in terminal, you will be prompted with Display all 870 possibilities? (if you're using Panther Client) or Display all 963 possibilities? (if you're on Server). Type y, and you will see a list of all BSD commands.
[robg adds: This only worked for me in the bash shell, and I've installed a few extras, so I see 1,023 possibilities on my client install.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20031104134841225