Electrical meter

Tire air gauge

Tire patch kit

Air pump

Brake reset tool (forget exact name, I paid $10 and it pushes the brake piston back in when installing new brake pads)

Tire thread measuring tool (know when you need new tires)

Battery tester (test how many cca remain)

Battery acid tester

Radiator coolant tester

Distilled water to put in battery

Coat hangers (metal hanger can be cut and bent to hold things such as the brake caliper)

The tire patch kit saved me a few weeks ago.