On the right hand side of the screen, go to "My Pet Collection" and select manage.
There will be four tabs in the middle of the screen. My Collection, Update Collection, Customize List, Print Checklist.
First, select Customize List. Take out any categories you can't/won't ever collect. Then, save that, and go to Print Checklist, and look at Uncollected pets.
That will give you a list of everything you don't have that you could conceivably collect.
Or, you can go to the "Wanted" tab under My Collection, after you've Customized your list, and then you can filter THAT to show drops, vendored pets, quest and achievement awards, etc.
And always "Update your Collection" on a regular basis.
Thaliana#1794 - My WoW account has 50 toons, so I would so greatly appreciate people creating toons on Kael'Thas or Ghostlands to trade with me. <3