Keyboard shortcuts:

F3+?:

F3+ a letter can help you. Reloading texturepacks or showing chunkbordes or just crash your game! Here is a list with every usefull combination:

• F3+c -> Copy location or crash Game when hold for min 6 sec
• F3+t -> Reload texturepack
• F3+a -> Reload Chunks
• F3+h -> Toggle advanced item tooltips
• F3+g -> Show Chunkbordes
• F3+D -> Clear Chat
• F3+F4 -> Change Gamemode
• F3 -> Show debugscreen

Other shortcuts:

• F1 -> Hide GUI
• F2 -> Capture a screenshot
• F5 -> Changing camera view
• F11 -> Toggle Fullscreen
• Middle mouse button -> Get the block you are looking at (only Creativemode)

All these combinations can change in the future or some in the settings.