cantelope
Pokeball
Just about any object you care to name. If you make something bigger or smaller, you can usually make it weigh exactly 1 kiogram.
a laptop mouse,watch,pen,pencil,
Note: Kilogram is a unit of mass, not of weight. A small bag of sugar, salt, or flour might have a mass of 1-2 kilogram; a small jar of water will also have a mass of about 1 kilogram.