Equibase for thoroughbreds is a purchase per report type but they will have everything that is registured with the Jockey Club. Thorougubred Times website has a progeny selection on the left side of the screen for free but I think it only covers offspring that have gone thru a sale. (not really sure about that). You can also look at the Bloodhorse stud book and the Thoroughbred Times stub book as each page will have lots of info on stallion progeny. Hope this is what you were asking.