What if you only had one tool to do woodworking with? What would it be?
In all honesty, a narrow chisel. I can hit it with a rock to chop mortises. I can pare away material to make tenons. Stick it through a block of wood, and it's a router plane. Stick it through a differently shaped block of wood, and it's a rabbet plane. With sufficient time and care, it can cut, shape, smooth, and just about anything. Box joints, mortise and tenon, even grooves and dados.
I wouldn't WANT to, but someone with enough skill (and time, and good sharpening stones) could furnish a house. There'd be a lot of weird joints, and a lot of waste, but it really is just about the most versatile tool in the shop.
Yes, I know everything can technically be done with just a chisel as some Youtube woodworkers have shown, but that just looked exhausting.
I guess what I'm really considering is like your circular saws, drills, jigsaw, routers, planers, table saw, etc type tools.
Up until recently, I could only use my power tools in good weather, because I had to run a power cord from the house to power anything. So.... none of those things have been in my daily use. If I could have my hand tool kit plus one power tool, I'd go with a circular saw, I think. I can do everything I need to do with hand tools, but ripping long pieces of lumber by hand just sucks.