I hit a milestone this past Saturday...the 2,500th different person to appear in my NBA collection! This is a big deal, because...well, it's 2500 different people, but also because I have been actively trying to get every different person who appears on an NBA card into my collection.
It's hard work. There are a lot of obscure people who only get on one card. There are also a lot of pioneer era players who only got one card each, in 1948 Bowman, 1957-58 Topps and 1961-62 Fleer; each of those sets is fairly expensive for even the common players. Even with hitting the 2500 mark, I still have almost 500 people missing from my collection. Possibly more than that, considering I find out about new people with rare cards on a regular basis.
I doubt I will ever be able to get everybody who has a card into my collection. Aside from the expensive old timers, there are some people thrown into sets that only have one card extant. Luckily, it's a college only coach that they had sign a SN1 autograph for an NBA set, so it's peripheral at best.
It does include more than just NBA players. It also includes coaches, and ABA players, even those who did not play in the NBA or at least not get NBA cards.
It does not include college issues, multi-sport or unlicensed issues- those are NOT NBA cards.
It also does not count shared cards; there are a couple of people who did not get their own cards. Joe Crispin in 2001-02 Inspirations is the only one not on a League Leaders card I can think of off the top of my head. It DOES count the people who only got cards in 1980-81 Topps, as they are separate cards that happen to be stuck together.
There is also the possibility that I have not counted right, although that's doubtful as I let the computer count for me...it's much more likely I've listed somebody more than once, or missed listing somebody, for example, when I wrote down all the people in my collection, which I then typed into an Excel chart...I somehow missed Larry Bird. If I could miss somebody that big of a deal, than I could easily miss somebody else. I am currently in a multi-year long process of fully figuring out my collection- I started in 2013, and I doubt I will finish this decade.
Anyway, here is the card of person #2500 in my collection. It's not a very good card. The Excalibur set is one of the worst designs Panini has used. Still, a card's a card.