The major sports have a domain (sport)-reference.com. How do you manipulate the parameters of the search?
At MLB’s I want to see the stat leaders as of 1899.
At NBA’s, I’m looking for anyone with a better FG% than FT%.
Those are very different requests. I’d suggest looking around a bit more at what the various options are for displaying data at each of those sites, because there’s a lot going on to get your head around, and you can’t do basically anything from the general site search.
To answer your specific questions, what you’re looking for at baseball-ref are the leaderboards called “Progressive.” They’ll have the career leader for each statistical category year-by-year.
For the NBA question, and probably for the best answer to your question generally, you need to use the “Play Index / Season Finder,” which is a pretty sophisticated tool, considering that it’s free. Like so.
TY for the NBA answer! The top 2 were exactly who I suspected they’d be. 
For the MLB one, I meant career leaders. (is it possible to find that? ESPN wasn’t helpful)
The progressive leaderboards I referred to are career leaderboards.
Jimmy-Thanks! I was better at explaining what I was looking for than I thought. BTW, Cy Young has been the winningest pitcher since 1903! :eek: