This is a pack of all sound effects and ambiance from Knytt, and the soundtrack.
Here it is.
In Looki's extraction pack, all songs and ambiance were renamed to "SongN" and "AmbiN", and he didn't extract the sound effects.
This time, I kept the original filenames, so you can finally see what the ambiance is, and I also extracted the sound effects.
The songs are the oggs from the Knytt OST on Niffpage, as they're a much higher quality than the oggs in the game's exe.
They're also the same loudness as gameplay (some a bit louder, but close enough), because Knytt lowers the volume of some songs (the internal oggs are loud), unlike KS.
The Secret Game song is not in the Knytt OST, and I couldn't find a high quality version, so I extracted it from the game.
When you don't need to edit or mix the sound effects, you can use
this ogg pack (songs and ambiance not included)