Have you considered creating an exportable spreadsheet? I created my own spreadsheet to help my collection efforts. It shows all the currently available pets in game, has four columns for grey, white, green, and blue pets, and shows what level pet I have in the appropriate column. It then shows the highest tameable level, and lastly where I can obtain each pet at that level. That last column is only filled in sparsely as most of my pets are at or near the highest tameable level.
Most internet databases can be used to create spreadsheets and most of the things in my spreadsheet are easy to create. The hardest thing about my database wasn't its creation but the need to constantly update it. My data here is very easy to update and having the option to export it would make my efforts much easier.
I'm not sure how popular a feature like this would be. But for people like me who are going for all blues (I'm at 124), this format is a great way to support those efforts. Thank you for your great web site.