Edit: Ok, since some of you like being silly and this is a video game website, you can include game related and fantastical items. I guess that makes things more interesting.
What do you think would be useful? You don't have to list everything you think you can fit in. A couple of items you think will be useful is good enough. Hopefully some interesting items will be discovered through this. You can include food and beverages as well. I'll start:
- Multi tool
- Ice tool
- Magnesium fire starter