small potato

Small/big potatoes.

小人物 微不足道的人 無關緊要

e.g.

I didn't realize you were small potatoes.

And to be clear, I am referring to your testicles.

Hot potato.

炙手可熱

e.g.

The subject of abortion become a political hot potato.

Potato Head

傻瓜

Potato digger

古板 不受歡迎的人