1. Shell: Shell is one of the earliest currencies. Around 3000 BC, they were used in commercial transactions in China. Shells have also appeared in ancient Egypt, ancient India and Sherpa culture.

2. Stone: In Central America and Northern Europe, stone was once used as currency. These stones usually have a specific color or shape for easy identification and differentiation.

3. Animals: Animals are also used as money. For example, Indians use deerskin, and Eskimos in the Arctic use seal skin.

4. Grain: Many early societies used grain as money, such as ancient Egypt and the Roman Empire. These currency forms were not adopted by all ancient civilizations, but depended on the environment and demand at that time. With the continuous progress and development of human society, money has gradually evolved into a more perfect form and become an important part of the modern economic and financial system.