Here's a reference of the current files used for Worms. It's highly recommended that you download every single one and try to keep your own soundbank folder in sync with the list below (deleting and adding as necessary so you don't accidentally use one nobody else has). Leave a reply if you want to have a new sound bank added to the list, etc.
Official Patch v220.127.116.11 (June 29th, 2007)
Applies the latest fixes and changes to the game.
Sound Effect Pack
Replaces almost every single sound effect with a high-definition counterpart, while carefully preserving the Worms feel and the signature sound effects (eg: the Holy Hand Grenade's 'Hallelujah!' was restored from the original song in much higher quality).
Sound Banks (March 24th, 2008)
The many voice packs we use. You should definitely get these as we made a lot of them ourselves and actively use them all the time; simply make sure each one is placed as a folder in the \Data\Speech\
folder. I've put the names of the people who made/use them next to each pack so you know which ones not
to use if you're not that person. Please leave a reply if you want to claim an unused soundbank or add your own.