Note that there are only 22x22 versions of the Oxygen emotes.

[edit] Specification compliance of icon names

Icon names without trailing stars already exist in the freedesktop.org icon naming specification.

 face-angel               OK 0:-)
 face-angry               Needed X-(
 face-confused            For which emote? (not in the spec) **
 face-cool                Needed B-)
 face-crying              OK :'(
 face-devilish            OK >:-) (was named face-devil-grin in 0.8
                             of the spec, but is now renamed there)
 face-devil-sad           -- gone from the spec in its current
                             CVS version, no need to draw this emote
 face-embarrassed         OK :-[
 face-foot-in-mouth       Strange name? for which emote?
                          (not in the spec) **
 face-glasses             ?? (gone from the spec after 0.8)
                          The new spec defines face-cool instead
                          of face-glasses for B-), which might
                          mean that this one doesn't fit as well?
 face-kiss                OK :-*
 face-laughing            -> face-laugh :-))
 face-monkey              Needed :-(|)
 face-plain               OK :-|
 face-raspberry           OK :-P
 face-sad                 OK :-(
 face-sick                Needed :-&
 face-sleep               For which emote? (not in the spec) **
 face-smile               OK :-)
 face-smile-big           OK :-D
 face-smile-gearhead-female  OK **
 face-smile-gearhead-male    OK **
 face-smirk               Needed :-!
 face-surprise            OK :-0
 face-tired               Needed |-)
 face-uncertain           Needed :-/
 face-wink                OK ;-)
 face-worried             Needed :-S

 * suggesting this for inclusion into the icon naming specification
 ** not in the spec, but let's keep it out of there anyways,
    it's not really suited to be a standard icon

[edit] To do for Oxygen

Icons that are in the spec, but not yet in Oxygen's emotes/ so they need to be added. Descriptions taken from the specification.

 face-angry
   The icon used for the X-( emote.

 face-cool
   The icon used for the B-) emote.

 face-monkey
   The icon used for the :-(|) emote.

 face-sick
   The icon used for the :-& emote.

 face-smirk
   The icon used for the :-! emote.

 face-tired
   The icon used for the |-) emote.

 face-uncertain
   The icon used for the :-/ emote.

 face-worried
   The icon used for the :-S emote.