There are a few things that everybody should keep in their repair kits that don't seem to go in one, but I've found these things to be useful multiple times.
1: Twisty Ties
You may know them as bread ties or garbage ties, those little wires covered in plastic or paper that can be used to tie things up with just a twist. I've mostly used these to keep cables nice and tidy. I've also used them in computer repair to keep things in place, mostly fans, but I have used them to successfully mount a hard drive when there wasn't any screw holes :P
2: A Needle
Yes, a needle, like the ones used for sewing. I use these in my cleaning process for gaming equipment to easily get the dirt out of the cracks without taking something apart. They also come in handy when you need to realign a pin in a tight space.
3: Daily Pill Box
You know, the ones with SMTWTFS on them. They are great for holding screws, and keeping them separate for each stage of disassembly.
These things will make a good repair kit great, trust me :)