Well, I have 6 dogs, mine is Pit Bull, she can do all kinds of tricks, she can turn on the lights, open drawers, open the door (the outer door is not a round handle, so she can bounce and open it with her paws).
She can bring me toys that are named after me, when we go for mail, she brings paper. Of course, she can sit, lie down, roll over, five, shake, count, this is largely the basis.
But her one least useful skill is the ability to walk on a leash, because I never use a leash on her unless I’m somewhere that requires a leash. Seldom, she usually just follows me like a leash. So this skill is pretty useless, she knows how, but I don't use it much. Once she was on a trampoline, and I did not teach her this, but she did a backflip on a trampoline, and for some obvious reason, when she landed, she looked so happy, she smiled, and she continued to do it, I was embarrassed but I guess it is her skill that is completely useless and she just loves to do.
This helps me with training and diet, which consists of Holistic Select Small & Mini Breed Adult Health Anchovy, Sardine & Chicken Meals Recipe Dry Dog Food, 4-lb bag