What’s One Digital Tool You’d Keep in Your Emergency Kit?

[galaxyswappersv2]

When people talk about preparedness, we usually think about food, water, first-aid supplies, flashlights, and other physical items. But I think digital preparedness is becoming important too. 
 

Keeping useful information, important documents, offline maps, and essential tools available can make a big difference if the internet or normal services become unavailable.

I also think it's worth being careful with third-party software and only using tools from sources you trust. For example, if you're interested in gaming-related software, you may come across tools such as Galaxy Swapper V2 , although that obviously isn't a preparedness tool.
What digital resources or offline information do you think are most useful to keep available during an emergency?