Every open league on this page is free to join with a Google or email account. The public One and Done pool runs every MLB postseason: pick one hitter and one pitcher a day, each player once all October, and the standings update from the box scores overnight. Public October Box Pools and Playoff Draft leagues appear here whenever a commissioner opens one to everyone.
Want your own group instead? The fantasy baseball leagues page has every format; the league rules cover scoring, locks and tiebreakers for each.