I saw that either F5 or F7 makes a picture and saves it to folder "screens". This includes the HUD, so it is a screenshot shortcut. Or, let's all press what buttons will come and tell about the functionality of them here!
If we're really resurrecting this thread then here's a few more shortcuts/things:
WASD - drive
space - fire weapons
shift - fire boosters/vertical propellers.
alt - deselects current held block while alt is held.
alt (double tap) - deselects current held block.
ctrl + click - selects or deselects multiple corps/categories in the inventory.
L - opens mission log.
esc, p - closes current window/opens pause menu.
tab - opens or closes inventory.
numpad up, numpad left, numpad right, numpad down - WASD for left-handed people.
x - detonate exploding bolts.
b - enter build beam