Cockatoos, cockatiels, and parakeets but they're all loud and bite without warning. Female rheas and ostriches can be really cuddly and more predictable. I knew an ostrich that would lay down and stretch out her wings for belly rubs while the rheas followed humans around like bird dogs.

edit: And hens. Silky chickens in particular are so affectionate but if you get them in a group hens are vicious toward each other.