This is a resource for builders.

Approximately 2450 sounds from freesound.org, re-encoded and renamed by myself so they can be used in nwn2. I have also provided nwn2 sound blueprints for each sound. This is roughly 10x the number of sounds nwn2 includes via the toolset. This pack is complete with blueprints organized into categories based on default nwn2 sound organization. Sounds from freesound.org are licensed under one of four Creative Commons licenses, see the credits for specifics. The filenames had to be shortened for nwn2, so the initial number matches the number of the file on freesound.org (the numbers are unique).

Sounds have been grouped into 4 groups of approximately equal number of files. You probably want to download all four groups, and select the sounds that work for your module or campaign, removing the rest. The sounds should be copied to your module or campaign folder. The blueprints go in the same location, and will appear in the toolset under the freesound.org category.

Blueprint categories, all are under the Freesound.org category:
Background and Ambient: similar to the default Background category, plus sounds that make for good area wide ambient sound
Cave: sounds most likely to be found in caves, things like rubble.
Chatter: Same as default, sound for groups of people, crowds etc
City & Town: same as default, most useful for placing in cities/towns, generally the sound of work being done
Creatures: same as default, creatures, animals, birds, vermin
Dungeon or Creepy Sound: sounds most likely to be used for dungeons or creepy effects.
Environmental: same as default, sounds of water, fire etc.
Human Vocalization: individuals speaking, coughing, etc.
Instruments and music: both single notes being played, and melodies
Modern Day House: sounds from real life, lawnmowers, microwaves and such
Sci-Fi sounding SFX: hopefully self explanatory
Short SFX like clicks or beeps: brief sounds for use as button presses or the like.

I categorized the sounds by listening to them, so things are likely not perfectly categorized.

Not sure if these will work in NWN1, as I do not build for that game.

If someone was going to make a "curated" pack, as had been suggested, the prime places to look for extraneous sounds would be the Sci-Fi, Modern Day House (both these categories could be removed with little effect for most builders), Creature sounds (there are tons of bird sounds), Environmental water (lots of water sounds), Instruments (lots of single note sounds) and the Background and Chatter categories (these two categories have many of the larger files).

Credit to Tchos for working out how to batch convert sounds for use in nwn2. (http://social.bioware.com/forum/1/topic/163/index/12546943#14386608)