Mouselook (M) - Puts the user into mouselook mode (first-person view). Mouselook is usually used for vehicles and weapons but can just be nice to use and feel immersed in SL instead of detached from your avatar. Portions of the interface are hidden in mouselook mode, and can't be accessed, such as inventory. However, interaction with the world is still possible (such as moving or clicking objects).
Inventory (Ctrl-I) - Opens/closes the inventory window.
Muted Residents - Shows the muted residents window which gives you a list of residents and/or objects you have muted overtime with the ability to unmute them.
Camera Controls - Opens a window that has buttons for controlling the camera with mouse clicks.
Movement Controls - Opens a window that has buttons for controlling the movement of your avatar with mouse clicks.
World Map (Ctrl-M) - Opens the World Map Window, giving you an overview of the world with many togglable legend icons.
Mini-Map (Ctrl-Shift-M) - Hides or shows the mini-map, a small map showing what is immediately around you, objects owned by others are represented by dark grey clumps while objects owned by you are in a teal. You can change the zoom distance of the mini-map or stop tracking locations by right clicking on it and selecting an option from the popup menu. The mini-map can be changed to rotate with the avatar or stay locked to cardinal directions by going to Preferences > General > Rotate Mini-Map.
Statistics Bar (Ctrl-Shift-1) - An unmovable bar that displays various technical information such as clientFPS (frames per second), bandwith, sim FPS (how many frames per second the sim is moving at), time dilation, and other various statistics. Clicking a statistic will cycle it through different styles of displaying the information.
Property Lines (Ctrl-Alt-Shift-P) - Show how the parcels around you are divided. Parcels owned by other residents are outlined in red lines, parcels owned by yourself are outlined in green, land for sale is outlined in orange, land for auction is outlined in purple, and land owned by a group you belong to is outlined in teal.
Land Owners - Highlights land parcels around you in various colors. Land owned by others is highlighted in red, land owned by yourself is highlighted in green, land for sale is highlighted in orange, land for auction is highlighted in purple and land owned by a group you belong to is highlighted in teal.
Hover Tips - Shows a submenu that controls what tooltips (proper name) are visible to you.
Show Tips (Ctrl-Shift-T) - Toggles all tooltips, includes land tips, avatar name tips, and object tips.
Land Tips - Toggles tooltips for land only.
Tips On All Objects - Toggles tooltips for objects only.
Alt Shows Physical - When the Alt key is pressed, physical objects will be highlighted in red if enabled.
Highlight Transparent (Ctrl-Alt-T) - Highlights all prims that use transparency in red. Both objects that use transparency from the Edit menu and objects that use transparent textures are highlighted. This is useful for finding "hidden" abusive prims.
Beacons - Shows a submenu that allows toggling of beacons for certain object types.