While the Warriors site is fun, it's a little harder to navigate the books, and used to be blocked at our school under "games".
The Fantastic Fiction web site has a great list, complete with covers AND all of the books, including the Manga. New Releases are mentioned as well, all on one convenient page.
The main series by this author are Warriors (6 books); Warriors: The New Prophecy (6 books); Warriors: Super Editions (4 books) ; Warriors: The Power of Three ( 6 books); Warriors: Omen of the Stars (4 books); Warriors: SkyClan and the Stranger (2 books); four Warriors guides and Seekers (6 books).
38 books, plus 12 manga, are a lot of books, so I am starting to understand why a lot of elementary libraries have not made these purchases. I would not have started buying this series if a very devoted teacher hadn't donated half a dozen books.
I finished the last Seekers book last night. It's been interesting having conversations about the series with the die-hard fans, many of whom are so dedicated that they even surrendered their library books briefly so that I could read them over the weekend! None of them are surprised that I have trouble giving a plot description of individual books.