They're all on Gutenberg (and on manybooks.net, which I find easier to use) except, for some reason, Anne of Windy Willows/Poplars.

I think Rilla is my favourite book after Anne of Green Gables - makes me cry every time I read it! Some of it is irritating, of course, and Anne does not improve with age, but it's almost as good a coming-of-age book as Anne of Green Gables.