Servants of the Empire and The Rise of the Empire
If you picked up the Rise of the Empire paperback it collects three new short stories. One takes place between Lords of the Sith and Tarkin in 14 BBY (although Mercy Mission says it takes place a year after Lords of the Sith, it is really only "about a year" according to the author and takes place before Tarkin), Bottlenck takes place before A New Dawn, and the last one, The Levers of Power, takes place during the Battle of Endor. They are decent little stories, worth reading, but I hated having to pay for two novels I already had just to get these stories. Seems like a cheap trick on their part. However I better get used to it because I'm sure it'll happen again.
The other new book I added to the timeline was Servants of the Empire: The Secret Academy, which wraps up Zare's story. It seemed a little rushed at the end, but other than that this four part series was pretty interesting and weaved in and out of Season One of Rebels. Where it fits in the timeline is easy to find, although it is actually best read out of chapter order. Take a peek at where I put it in the timeline and you'll see I actually have Ch.12 first. You can read it however you like, but if you are trying to read it chronologically with the Rebels episodes, you'll need to do it the way I suggested.
Next up are the comics from this month, and then the novel Battlefront: Twilight Company. There are some other short stories coming out starting around the end of November which can be found as ebooks.