I don’t just mean a wrench, unless thats it for you. I mean any tool you regularly use for work that you consider your most important. If you’re a software person name whatever digital tool you guys use. Whatever the career everyone uses tools I dont care if they are digital, verbal, physical or psychological. For me its honestly probably a flashlight, before I use any tools I’m always investigating with my flashlight or using a laser to trace lines.
My most used tool is a cordless impact driver. With the right bits it is so useful. Cuts many repair times down to a percentage of their non impact driver repair time. I have bits for any screws and also bits to adapt sockets.
The one I picked up is less than $50 at Walmart with the bits. Super useful tool to have around. I throw it in my backseat and it’s always there when I need it.