A Grenade.
Spear most likely, it can be thrown too.
boomarang
yes why do you think knights use it?
Light saber
Yes.
The European knights wore a suit of armor and their weapon is a sword
Yes.
A stone that could be thrown .
A silver knife, thrown by Bellatrix.
The main weapon used by knights during the Middle Ages was a sword. It was a versatile weapon that could be used for both cutting and thrusting in battle. Knights also used other weapons such as lances, maces, and axes depending on the situation.
Probably as a weapon to be thrown, or as a cave shelter.