Now that Leland has removed the "Options" from the export dialog (for the upcoming 2.1.2) these should be more discoverable.

I would be loath to extend the dropdown menu from the "Save as type" to include these more obscure (less frequently used) formats.

The main problem is that the wording "Other uncompressed files" may not be clear enough to encourage users to explore that - so maybe we should think about rewording that for clarity of purpose. 

Once you have clicked on that though, the "WAV(Microsoft)" is shown as the default container in the "Header" selection box.  It is then a simple matter to explore the "Encoding" dropdown to select the encoding such as U-Law, A-Law and the various forms of ADPCM.

See this Forum thread: http://forum.audacityteam.org/viewtopic.php?f=46&t=87963

Added RF64 to title which is also a problem. Users don't realise the 4 GB WAV/AIFF limit and can't find the option they need, then complaining that their exported WAV is truncated.

(In reply to Peter Sampson from comment #1)
The formats in "Other uncompressed files" are in fact all formats other than AIFF 16-bit, WAV 16-bit and WAV 32-bit float that libsndfile handles. Given FLAC is in "Other uncompressed files" on Linux (as well as having its own entry) and that users think *-Law/*DPCM are compressed when they are strictly speaking uncompressed), it's hard to see what it could be called. 

Clearly we cannot just call it "Other libsndfile formats" while there are important formats inside it. Users can of course now explore the lower two dropdowns, but the long list of headers and encodings there may look obscure and intimidating. 

Therefore it makes sense to me to move the most important formats in "Other uncompressed files" (three extra items as per the bug title) into the root of the menu. Then the ambiguous "Other uncompressed files" moniker does not matter so much.

Another approach suggests shortening the root menu so that it contains only our assessment of what are the "common" formats plus generic "Other compressed" and "Other uncompressed" items containing everything else, regardless if libsndfile or FFmpeg encodes it. There is a Forum discussion about it (see URL).

I do not recall many (if any) recent support requests for suchlike on the Forum.

And I am somewhat loathe to extend the "Save as type" dropdown menu in the File>Export dialog - it's pretty long already.

RESOLVED WONTFIX in view of comment 4, and lack of enthusiasm for making this change amongst developers.