The suggestion to include no-longer-available and past promotional pets to the Trading Post isn't a new one. I think lots of people have floated the idea around.
This is just a full list of possible pets that fall under the aforementioned categories, for reference and easy viewing. I recognize that some battle pets on this list are probably completely off limits and would never be considered by Blizzard for the Trading Post (for various reasons), but I've included them anyway for completion.
So here are all no-longer-available and/or past promotional pets that players would probably like to see in a future Trading Post rotation. Let me know if I've missed any.
Trading Card Game Pets (TCG)
- A few of these have already been offered again, through Twitch Drops/other promotions, but I'm still including them. You never know, maybe some people missed out on those giveaways.
- Bananas
- Dragon Kite
- Ethereal Soul-Trader
- Eye of the Legion
- Gregarious Grell
- Gusting Grimoire
- Hippogryph Hatchling
- Landro's Lichling
- Landro's Lil' XT
- Nightsaber Cub
- Purple Puffer
- Rocket Chicken
- Sand Scarab
- Spectral Tiger Cub
- Tuskarr Kite
Collector's Edition Pets (across all Blizzard IPs, not including currently available ones)
- Anima Wyrmling
- Baby Winston
- Baneling
- Drakks
- Dread Hatchling
- Fetish Shaman
- Frosty
- Lil' Deathwing
- Lucky Quilen Cub
- Lurky
- Mini Diablo
- Mini Thor
- Netherwhelp
- Nibbles
- Panda Cub
- Tottle
- Treasure Goblin
- Zeradar
- Zergling
BlizzCon Pets
- Deathy
- Finduin
- Gillvanas
- Grommloc
- Grunty
- Knight-Captain Murky
- Legionnaire Murky
- Moon-Touched Netherwhelp
- Murkablo
- Murkalot
- Murkidan
- Murky
Recruit-A-Friend Pets (not including currently available ones)
- Golden Pig
- Jade Tiger
- Rikki
- Silver Pig
- Zipao Tiger
World Event Pets
- Hatespark the Tiny
- Spirit of Competition
- Vampiric Batling
Misc Promo Pets
- Gryphon Hatchling
- Lucky
- Mini Tyrael
- Mr. Chilly
- Murkimus the Gladiator
- Wind Rider Cub
Region Promo Pets
- Essence of Competition
- Gurky
- Murki
- Onyx Panther
- Poley
- Spectral Cub
- Tiny Green Dragon
- Tiny Red Dragon