What tools do you need when building/working with a 3D printer?

So you have purchased a 3D printer kit, or are thinking of building your own 3D printer soon. What other tools do you need to build, maintain and get into 3D printing? Well here is a list of my top 5 tools that I use all the time when 3D printing:

This is a companion discussion topic for the original entry at https://reprage.com/post/48912565074/what-tools-do-you-need-when-building-working-with-a-3d