If you want to see all of the past Pets and Wings that you can no longer obtain, you can check out this Blizzard forum post by MissCheetah!

Even while writing this guide I had many people mention that Wirt's Original Leg is a myth and not an actual item, but behold, the item is indeed real! In this guide below we'll focus on Wings, Pets and Transmogs that are still available as opposed to the ones you can't find any longer.

Some are quite easy to obtain and others will make you think that the item doesn't actually exist at all. A lot of the cosmetics you see other players using are no longer available to obtain, but all of the Transmogs can be collected if you look in the right places! Many of these cosmetics are obtainable in game and can be found at any time, but there are also many that are rewarded from other Blizzard games as well as during new Seasons and Events. Diablo 3 is home to many cosmetics that you can gather as you adventure through Sanctuary including Pets, Wings and Transmogs.

Diablo 3 wing locations