The short answer is, a piece of carbon steel, a piece of handle material, some time and some tools.
A better answer is; to make a knife like some of the ones we see here, you need some pretty sophisticated tools and a working knowledge of how to put them to use. A considerable amount of space to do it all in. You need some understanding people around you that don't mind all the spare time used up for knife making, time spent with customers and the vacation time and airfare spent on knife shows instead of places like Cancun, and all the dirt.
A wife or someone else with a job that has benefits like health insurance is helpful.
Most of all you need a lifetime of dedication and devotion (to make some like the ones you see on here), a sense of style, almost an instinct for flow, balance and design.
Some of the things it takes to make a good knife can be acquired by anybody, some of them take a lot of work to get and some of them, you just have to be born with or find deep within you. It's an illusive thing.
A good knife should last a long time, feel good in your hand, do the job that it was intended to do well, move gracefully and touch something inside you.
Some of us "Get it", some of us will get it, some of us are working at it and some will just not understand.
One thing is for sure, you will not see a forum like this for something like a screw driver.
I'm sorry, I got carried away. I re-read you question and see you were asking more about materials. That's really the easy part. The knife making materials "for sale" area of this forum is full of the sought after materials for knife makers