Found some unused sounds in Worms 2 and WA a while ago. I wonder if they could be somehow enabled via mods and also, what was the purpose of Surf.wav and Uh-oh.wav? I'm also surprised nobody started something like this... Here the sounds:
Hmm.wav
Surf.wav (Is only shown in American soundbank files)
Wobble.wav (was intended to be used when falling from a high distance, as with the first Worms generation)
Uh-oh.wav (referenced by the game, but unused by the game engine)
Source:
http://worms2d.info/Soundbanks