List of sound packs?

Just a quick question.

I noticed there were sound packs ( I think it’s what they are ) but I was wondering where I could find a list or access them. Here is what it is.

[lua]“NPC_Hunter.Footstep”[/lua]

I know there are other kinds of “packs” like this one so, could someone help me?

Thanks.

[editline]12:50[/editline]
Nvm, found them, they are in the Source Engine gcf.