There are various keyboard shortcuts to use in SL2. Here is a non-exhaustive list.
Ctrl + Various : Emotion Bubbles!
A - Angry Bubble
I - Idea Bubble
R - Circle/Right Bubble
S - Sweatdrop Bubble
H - Heart Bubble
W - Cross/Wrong Bubble
! - Exclamation Bubble
? - Question Bubble
Typing 'Sing' into the chat as a command produces the 'Sing Bubble'.Ctrl + Arrow keys : In battle, moves the screen, useful for spacey battles.
Ctrl + Click : When used on a closed door, bashes it.
Shift + Enter : On the World Map, sets up camp.
Tab : Toggles WASD Mode on/off.
Delete : Toggles the game HUD.
+ / - : Adjusts area/size/length of certain combat skills.