Nice!
I found two more sources for free sounds:
http://pdsounds.tuxfamily.org/ (An old backup of pdsounds.org, before it died)
http://wiki.laptop.org/go/Sound_samplesActually, the second link is more fitting for the "Free loops and stems" category than "Free sound effects". However, it does have some sound effects, so it more-or-less fits both.
...Did you check https://archive.org/details/PdsoundsArchive
I decided to list
http://www.archive.org/details/opensource_audio under the
Music category because, out of the
millions of public domain and creative commons recordings there, over 98% of that seems to be music and voice recordings. To find a few exceptions that could be directly used as sound effects, let alone appropriate for DF and SoundSense, would be like finding a needle in a haystack.
The "
pdsounds archive" you link consists of 10 sound effects. That's the entirety of this collection. It does have 57 files listed. But that's because it offers the same 10 sound effects in various formats. As such, I don't think it's worth listing.
Archive.org is pretty impressive, it grabs content you think is otherwise dead at times.
I used to be impressed by Archive.org. It was so useful to look at an old site, esp. after the original is gone. But several years ago I noticed more and more archived sites filled with nothing but broken "snapshot" links. And more and more sites are not cached/archived at all. Or they won't show you what they have. What is the point of "preserving" the Internet if they turn around and
delete their content or otherwise
block the public from browsing what they have?
Around the same time, they broadened their scope to host books, music, software, and videos. Heck, if you click anywhere below the top third of their home page, the WaybackMachine search field disappears. Clearly, their search field for books, music, software, and videos is meant to be the site's (and their organization's) new focus.
I still find Archive.org useful on occasion. But, anymore, I find Google's cache of a site to be more reliable.