Owls

I like the idea of owls similar to those in Harry Potter. This would be a very cute non hostile mob with a small inventory which you could use to deliver items to friends locations much like a bed that has a spawn point you could have a perch that the owl could land on. Tameable and found places like snowy tundra biomes, pale oak and dark oak forests giving the opportunity for different owl species. Much like a parrot it could also sit on your shoulder offering an extra 5 slot inventory. They could also drop feathers much like chickens but without having to kill them.