I couldn't think of a better place to post this, so Moderators, please feel free to move as needed...
If you're a patron of the Harris County library system, you have probably used (as I have) the link on the home page that takes you to their Overdrive library at
http://hcpl.lib.overdrive.com/ . However, I recently found more e-books (at least there were no duplicates in what I looked for.)
If you start at the home page,
http://hcpl.net, and click on "Catalog Search," and then choose the "try the new catalog" tab, you get a whole new search engine. Under the category of "electronic resources," there are bunches of books that don't appear in the Overdrive library (among those that do, of course).
A direct link to the search page, with a filter for just ebooks is:
http://hcpl.ent.sirsi.net/client/webcat/search/results?qu=+&qf=FORMAT%09Format%09ER%09Electronic+ Resources
I hope this helps somebody...
Curt