Noahdeer of Be MOP has posted a shared topic question on Blog Azeroth about collections:
World of Warcraft has added many different items for players to collect, whether it be collecting pets, mounts, transmog gear or knickknacks about the lore. This week’s topic asks what you do collect in the game and what is your prized item from that collection?I collect things both in real life and in-game. It's part of being a hoarder. I also like to be thorough and so once I start something I like to finish it. I'm also stubborn which helps. In-game I collect a number of things both physical items and non-physical.
Battle Pets
This one is pretty obvious to anyone who reads my blogs (but if you're new to my blog then maybe not. Also Hey!). Even before the announcement of pet battles I collected companion pets buying them as and when I could. When pet battles was announced I worked really hard to get as many of the then available pets as I could. Since MoP I have continued collecting pets. I manage my collection on warcraftpets.com and you can view my collection here. I currently have 413 unique pets. Obviously, I still have a number of pets to collect and level. I also need to complete Raiding with Leashes.