As for what can be found there: obviously it’s possible to put any data whatsoever on the dark web. But the main reason why people would put anything there is that they would get in legal trouble if they did it on the clearnet (= the ordinary, non-dark-web Internet). So if you’re not attempting to do illegal things, you probably won’t get much value out of it.
Someone else explained Tor already.
As for what can be found there: obviously it’s possible to put any data whatsoever on the dark web. But the main reason why people would put anything there is that they would get in legal trouble if they did it on the clearnet (= the ordinary, non-dark-web Internet). So if you’re not attempting to do illegal things, you probably won’t get much value out of it.