Tools.. Well in addition to the normal "every day" tools, (Knifes, cutters and pliars and screwdrivers)
Multi-meters (I have several) including a clamp on AC/DC ammeter.
Test lamps, both 12 and 120 volt,, again, nature of me is to have multiple and different sizes.
Electrical tape, sealant and connectors and in some cases special tools for dealign with the connectors (This last is optional but necessary in my life).
I have a few more things too but... Well.. I'm a certified electronics technician and a licensed ham radio operator.. Most folks do not need get as "into" electronics repair as I do.