TMNT 2K3 On DVD

[Monkey Ambassador]

So, I'm trying to catch up on my DVD collection. These are the DVDs for the 2k3 series that I know have been released:

In seasons:
Season 1 (Part 1)
Season 1 (Part 2) (I know this one isn't out yet)
Season 4

Non-season DVDs:
Volume one
Volume two
Volume three
Volume four
Volume five
Volume six
Volume seven
Volume eight
Volume nine
Volume ten
Volume eleven
Volume twelve
Michelagelo's Christmas Rescue
Volume thirteen
Volume fourteen
Volume 3.1
Volume 3.2
Volume 3.3
Volume 3.4
Volume 3.5
Volume 3.7
Fast Forward: Future Shellshock

My questions are: Are there any episodes missing? Are we expecting them all to be released in seasons or should I go ahead and buy whats already there?