Hey. So I've gone and compiled a list of emoticons from the sharedassets0.assets file.
Enjoy.

(A) Button A
(B) Button B
(X) Button X
(Y) Button Y
* Tiny Star
(G) Gold Resource Icon
(W) Wood Resource Icon
(S) Stone Resource Icon
(P) Black Powder Icon
(SK) Skull Icon
(D) Shield Icon
(H) Love Heart
(T) Clock
:) Emoticon - Smile
:D Emoticon - Laugh
:( Emoticon - Frown
:| Emoticon - Annoyed
>) Emoticon - Smirk
:'( Emoticon - Dead
>( Emoticon - Angry
>/ Emoticon - Rambo
(XP) Experience Icon
(TP) Talent Point Icon
(I) Inventory Icon (the small crate)
(FT) Fast Travel Icon
(+) Green Plus Sign (Medic)
(LS) Left (Analogue) Stick
(RS) Right (Analogue) Stick
(LB) Left Button
(RB) Right Button
(LT) Left Trigger
(RT) Right Trigger
(DP) Directional Pad
(DU) Direction-Pad Up
(DD) Direction-Pad Down
(Back) XBox Back
(Start) XBox Start
(?) Question Mark (duh)
(Yes) Talent Point Icon (Again)
(No) Red talent point icon pointing down
(IN) Padlock
LVL Talent Point Icon (... Again)
(ResHeat) Fire resist icon
(ResCold) Cold Resist Icon
(ResAcid) Acid Resist Icon
(ResEle) Electricity Resist Icon
(ResNether) Nether Resist Icon