Other stuff :

Mirror - a small mirror on a stick can help you perform the essential magic trick of seeing around corners. I always feel a little like a dentist when using mine.

Labels - handy for making notes, stick one to the inside of the removable panel of the case and detail the work you have done.

Paperclip - quite often lying around in offices anyway, there are many things a paperclip can be used for.

Rubber bands - as with paperclips, these can come in handy. Keep a few in your toolbox in case.