Scroll through quick-bar and the chat when opened

Pause single player game

Exit the chat / command window

Toggle heads up display (HUD)

Clicking item or stack will move it between inventory and stack

When a container is open, Shift + clicking on an item will move up to a stack between the container and the inventory

When a furnace is open, Shift + clicking an item or stack in the furnace moves it to the inventory

When crafting, Shift + clicking the crafted item automatically crafts the maximum number of that item for the materials being used (up to one stack), and moves all crafted items to the inventory

In the survival inventory tab of the creative inventory, Shift + clicking the X clears the whole inventory. In any other tab, Shift + clicking an item puts a stack into the hotbar

Toggle showing extra debug information

Display more detailed view of the graph on the right

Display Profiler graph

Reload all textures, sounds and web-loaded client resources. This is useful for resource pack makers

Toggle the auto-pause when the window is out of focus

Toggle detailed item descriptions

Toggle showing hitbox around entities

Cycle the player's game mode between Creative and Spectator

Show the chunk boundaries immediately surrounding the player

Sprint

Drop whole stack of items. On Mac, use shortcut below, because this shortcut will quit game