The Petty France blog has a page dedicated to Online Particular Baptist Resources, and it is definitely worth checking out. Here is the page description:
This page is dedicated to collating online links to copies of Particular Baptist literature (which are rare). PDF downloads of original sources are the preferred material, but transcribed works are useful as well. If you know of any, or if you find any, please leave the link in a comment, or send a message through the about/contact page, so that I can update this page.
Here at the Reformed baptist Blog we also have a page entitled Reformed Baptist Resources, and we welcome input for improving this page as well. It is a bit dated, and it would be good to make it more current.