Most people think that there should be special cards in this game that revolve around a baseball theme. For example:
Nine cards dealt instead of seven, called "nine innings".
Threes and nines wild, modelled after three strikes, three outs, nine innings, and nine players. Other people play that when a player turns up a card that is wild, they must pay for that card to be wild, a small amount like a quarter at a nickle-ante table.
If a player flips up a four, modelled after four balls and four bases, that player is dealt an extra card face-down from the dealt. Other people play that the player if a player flips up a four and wants the extra card, he must also pay for it, typically 50 cents at a knickle-ante table. Other than that, the card does not contribute anything to the hand other than being a regular four. However, getting the extra card can really help a hand.
Blind Baseball is not basic Baseball, only the more popular version. Basic Baseball (or just Baseball) is a standard seven card stud game, in which threes and nines are wild, and a four dealt face-up allows you to receive a new card from the deck. These threes, fours, and nines typically cost a player a predetermined fee in order to take advantage of them (at a quarter-table, for example, it may be a quarter for a three or nine to be counted as wild, and 2 quarters to get an extra card from the four).