Hide and show the GUI with a configurable keyboard shortcut (shift+F1 by default) to take screenshots with a full field of view. Optionally force daylight, alt-mode, and clear the chat/console.

Change the keyboard shortcut in Controls Settings > Mods (search for GUI), and change other settings in Mod Settings > Per player

For simplicity the mod uses a cutscene to reliably hide the GUI in sandbox and freeplay, but it doesn't work well if other cutscenes are playing. It's not possible to move the character while the GUI is hidden.