Basic Tools
You never know what you are going to need to do when you are camping. So it is smart to be as prepared as possible. Now you could bring an entire garage of tools, so it is best to narrow down what you might need.
As useful as it may be to have an axe, pliers, hammer… It seems most things that need to be done revolve around sealing, tying, or cutting.
For sealing, I tend to stick with the most useful tool in all of humanity… Duct Tape! I would suggest always having a roll of duct tape with you at all times. Even when not camping, it is a good thing to have in your car. If you don’t think it is useful you should go find the Mythbuster’s episodes where they use duct tape for all kinds of things.
It is common while camping that you might need to tie something. You may need to tie up tent accessories, tie up bundles of wood, or possibly tie up food or trash and hang it from a tree. You can get simple cord that will do all these things. You could also use twine, but cord is generally thicker and a bit more resilient. You typically want to look at 3mm or thicker for resiliency.
The other thing you will commonly need is a knife. Whether it is opening packages, cutting off stray twigs for kindling, or cutting off lengths of cord or duct tape you will likely need to cut something at some point while camping. Knives come in all kinds of shapes and sizes. I would go with a pocket knife for ease of use and storage. Nothing complicated is needed here.