Definitely the following:
- Ratcheting screwdriver with various bits (definitely phillip head bits)
- A 1/4 inch drive ratchet with sockets (deep sockets and short sockets)
- A torch
- Definitely a Leatherman
- and a telescopic inspection mirror
Optionals include:
- Side cutters
- Jewellers screwdriver set
- Lockwire pliers
My experience is mostly on heavies, so I hesitate on giving you what sizes you may need. You will learn what you will need from the person who is certifying your work (a brave man he is) and by cumulative on-the-job experience.
Good luck. I avoid light aircraft like the plague for good reason.