Which backpacks do I need to do a quest first so I can buy/exchange?

Question

As the main question says, which backpacks do I need to do a quest before I can buy them?

Answer 1

There is the list of the Backpacks you can buy after complete some quests:

•  Crown Backpack After completing the Astral Portals mission of The Explorer Society Quest, you will able to buy this backpack from and  for 800 gp.
•  Dragon Backpack.  After delivering 5 Tomes of Knowledge to Cael, you will able to buy this backpack from for 200gp.
•   After delivering 2 Tomes of Knowledge to Cael, you will able to buy this backpack from for 200gp.
•  Expedition Backpack. After finishing Mission 6 - Days Of Doom of The New Frontier Quest, you will able to buy this backpack from for 100gp.
•   Demon Backpack. After reach the rank Trophy Hunters of the Paw and Fur Society, you will able to buy this backpack from for 1000gp.

Source: Tibia Fandom