What networks are supported by Coinbase?

Can you please provide me with a comprehensive list of the cryptocurrency networks that are currently supported by Coinbase? I'm interested in understanding which digital currencies and blockchain platforms I can use to buy, sell, and trade through their platform. Additionally, are there any plans to expand their network support in the future, perhaps by adding new cryptocurrencies or integrating with additional blockchains? It would be helpful to know if Coinbase offers support for both mainstream and niche cryptocurrencies, and if there are any limitations or restrictions on the use of certain networks.