In case you aren't aware:
There is a third Teddy Mars book-- Almost as Outlaw.
(By Molly B Burnham, fun books)
There is a second Stick Cat book-- Cats in the City
(By Tom Watson, kind of Diary of the Wimpy Kid/doodle style)
There are, I believe, now three Ivy Pocket books. I am reading the first one right now (when I typed this... which is a couple weeks before posting... whatever) and it is BIZARRE. In good ways, you understand. Full review coming at some point, lol.
There is a sequel out to Riddle in Ruby-- The Changer's Key. Also book three The Great Unravel is out this year... I hope to get to these eventually.
There is a sequel to Fog Diver-- Lost Compass.