New answers tagged tosfot
You can try http://www.dafyomi.co.il/, choose any masechtah, and then scroll down. They have links for Tosafot for most masechtot, but unfortunately not for Bava Basra. And for books, you can try this wonderfully clear sefer called שערי תוספות, if you don't mind Hebrew.
Top 50 recent answers are included