Following are the keyboard shortcuts aviable for developer console:
CTRL+O = Open
CTRL+SHIFT+A = Open Lightning Resources
CTRL+G = Open log
CTRL+SHIFT+G = Open raw log
CTRL+ALT+G = Download log
CTRL+S = Save the current view
CTRL+SHIFT+S = Save all
CTRL+DELETE = Delete
CTRL+/ = Close
CTRL+ALT+/ = Close all
CTRL+E = Open the Execute Anonymous window
CTRL+ALT+E = Execute anonymous Apex code when the Execute Anonymous window is open or the last executed code when the window is closed
CTRL+P = View log panels...
SHIFT+ALT+G = Log panel
CTRL+SHIFT+? = Show/Hide help for the shortcut key
CTRL+F = Find
CTRL+SHIFT+F = Find/replace
CTRL+SHIFT+R = Find/replace all
CTRL+SHIFT+H = Search in files
SHIFT+TAB = Fix indentation
CTRL+SHIFT+O = Open resource
SHIFT+ALT+G = Clear log panel
CTRL+J = Show Preview of the Visualforce page/component
CTRL+ALT+N = Navigate to the declaration of a selected object in the Source Code Editor
CTRL+SHIFT+L = Show/Hide the Command Line Console
CTRL+, = Navigate backward through the view history
CTRL+. = Navigate forward through the view history
CTRL+PAGE UP = Navigate backward through the open views
CTRL+PAGE DOWN = Navigate forward through the open views
F11 = Toggle full screen editing of the current view, if available
ESC = Exit full screen editing of the current view, if active