In REDkit
When you have at least 2 objects selected in the world editor, you can press: M to open quick align tool.
To duplicate an entity in the world: Hold down SHIFT while moving an object on a checked-out layer to duplicate it.
Select an entity’s plane to move it on: press X/Y/Z or any combination of that to select the plane, and then click + drag along it.
When you want to move the camera, you can use: J to jump (teleport) the camera to the thing you have the mouse cursor pointed at.
And Ctrl + Alt + 0...9 to save current camera position and alignment. Ctrl + 0...9 will restore that saved position
In-Game (started from REDkit)
Basics
Alt + Enter - fullscreen mode
` - opens debug console
F10 - quit game session (terminates only game inside the editor window, not the editor itself)
F5 - quicksave (note: when editor is run in debugging mode on VS etc it's F6)
Pause Break - returns focus to the editor panels, pauses everything in the game window (click anywhere inside it to unpause)
shift + Pause Break - freezes time in the game, focus still on the game window, it's possible to use free cam mode after detaching the camera (use the shortcut again to quit the mode)
Time savers/hacks
+ or - (Num Pad) - increases/decreases time scale
NumPad1 - kills all enemies in the default range
NumPad2 - kills targeted enemy
Free cam/teleporting
F1 - free camera mode (press it again to quit it)
shift - quicker free cam when held
AWSD keys + mouse - browse the world on free cam
right click (mouse) - teleports player character to the specified place (useable only if the focus is on the editor panels = use Pause Break first)
ctrl + alt + c - copies current free camera coordinates
ctrl + alt + v - pastes free camera coordinates = takes the camera to the specified coords
u - photo mode
Debug
F3 - navigates forward in debugging pages or opens them if they are closed
F4 - navigates back in debugging pages or opens them if they are closed
F8 - opens debug windows