I actually collected them all, but I am a comics enthusiast who goes to a comic book shop every Wednesday, so I just had them on my hold box list. Overall I really enjoyed the series, though some were better than others. I think Big Thunder Mountain was my favorite, but Figment 2 was also really good. I also really liked Haunted Mansion. I do believe all of the series have been collected into books. If you search for "Disney Kingdoms Graphic Novels" on Amazon you can find them. Some are hardcovers, but I believe there are paperbacks that will be less expensive.
For the record they did six series:
Seekers of the Weird (based on the never built attraction that eventually became the Haunted Mansion)
Big Thunder Mountain Railroad
Enchanted Tiki Room
I do not believe they have plans to make any more. If you're looking for something similar, but that was not in this line, there is a digest sized Space Mountain graphic novel by Bryan Q. Miller as well that was really very good. It wasn't published by Marvel, but came out around the same time as the first Disney Kingdoms series.