Which baseball cards are worth money is best answered as a sorting problem rather than a list of players. A handful of features on the card itself predict, better than any name does, whether the card is worth ten minutes of your time. Pull those cards out, leave the rest, and check the small pile properly.
Anything with a number out of a number
A serial number printed on the card, showing it as one of a stated run, is the strongest single signal because it is a fact about supply rather than a claim about desirability. The smaller the run, the more the card's price depends on demand rather than on how many are lying around. These are worth checking first, every time.
Autographs signed on the card
An autograph applied directly to the card during manufacture is part of the card and is priced as such. One signed on a clear sticker and applied afterwards is worth less to most buyers, and the card usually says which it is in small print. Autographs obtained in person are a separate question, because a buyer cannot verify them from a photograph.
Dates before about 1980
Age is a proxy for a smaller surviving population. It is the reason the pre-1980 pile is worth checking card by card while the 1990 pile usually is not. Within that pile, condition then decides almost everything, so sort the old cards again by how sharp they are before you start searching prices.
What is not a signal
A famous player on a common card is a common card. A card in a plastic holder is a card somebody cared about, not a card somebody valued. A card that looks old is not necessarily old. And a card advertised as rare by whoever sold it to you is a claim rather than a fact; the print run and the completed sales are the facts.
Questions people ask about which baseball cards are worth money
What about error cards?
Some famous errors are genuinely valuable and most are not. The ones that matter are documented in set checklists and have their own completed sales; if you cannot find sales for an error, it is an error rather than a rarity.
Are complete sets worth more than the cards separately?
Usually less, for common years. Sets from overproduced eras are abundant and slow to sell, and the few cards worth anything inside them are worth more pulled out and sold individually.
Does a card being a rookie card make it valuable?
It concentrates demand, which helps when the card is also scarce and sharp. A rookie card from a print run of millions is still a card from a print run of millions.
How do I find out the print run?
For modern cards it is often printed on the card. For older ones it usually is not published at all, which is why age is used as a proxy and why the surviving population is read indirectly from how often examples come up for sale.