Two things which I took to instantly and now wouldn’t want to do without are an old-fashioned two foot, four fold ruler which gets used all the time (there’s nothing that comes close to it) and a 1 1/2″ butt chisel which gets used all the time for marking anything which needs to be chopped e.g. the side of a mortice. It also means fewer chops and therefore a bit more accuracy when cutting out a knife wall.
A try square is used to square up your workpieces for precise-fitting joints. If you’re not confident enough to build your own try square yet, you should purchase a good metal try square (somewhere between 9 and 12 inches). It’ll be used for scribing square lines around the faces and edges of your boards, such as a line for where to cut with your saw.
“Basic,” on the other hand, is a word that allows for growth – and that’s exactly what you want in your woodworking tool kit. You want to be able to take the same kit with you through many years in the craft. With my basic woodworking tools list, I wanted to provide a core set of tools that will serve you well from project to project. I’m especially concerned these days with the transition to hardwood furniture making, as opposed to plywood boxes of various sizes. That’s the transition I’m making right now in my own work!