Tokens represent a specific set of functionalities or hold a specific value on their respective blockchains. They are built atop existing blockchains, and there are various standards that determine their properties and functionalities. Some of the prominent types of tokens include:

ERC-20 - Represents a common list of rules for interchangeable digital tokens like governance, utility, or virtual coins.

ERC-721 - Defines a rule set for unique tokens, often associated with digital collectibles or specific digital assets.

ERC-777 - Extends token functionalities, enabling advanced features like enhanced privacy measures or mechanisms to retrieve access if private keys are misplaced.

ERC-1155 - Facilitates efficient token trading and combines multiple transactions to conserve resources. It caters to both generic digital tokens and unique digital collectibles.

ERC-4626 - Specifies a framework for yield-generating vaults, aiming to streamline and standardize their technical aspects.

These are standards specified by Ethereum. On other chains, there are similarly coded ones (e.g. BEP-20 on Binance Smart Chain, TRC-20 on Tron).

These standards essentially provide a blueprint that ensures the token has specific functionalities, such as transferring the token, retrieving the current token balance, and understanding the total supply of tokens.