Look for a laser protractor/digital inclinometer for beaming a straight line on anything. Aliexpress.

I DIY everything pretty much so it’s hard to think about what is basic. Set of screwdrivers. Light hammer, utility knife. Basic set of sockets and wrenches. Basic set of pliers. Cordless drill/driver. Caulking gun. Quality drywall anchors. Tape measure and a level. You’ll eventually need to fix small things too.