Summary of Apple Specfic terminal commands
Online References
Have you looked at this list? It seems to provide a pretty good library of OS X commands.
There is also an API Reference of the Mac OS X Man pages online here if you would like to see all possible commands.
On your computer
Although this is not a perfect list, you can grep (search) /usr/share/man with this line (first cd /usr/share/man):
find man* -type f -print | egrep -v '.gz$' | tr \\n \\0 | xargs -0 egrep -l 'Mac ?OS ?X'
(more verbose)
or
find man* -type f -print | egrep '.gz$' | tr \\n \\0 | xargs -0 zegrep -l 'Mac ?OS ?X'
(less verbose)