What types of cryptocurrencies exist and how do they differ from each other?

What types of cryptocurrencies exist and how do they differ from each other? There are many types of cryptocurrencies, each with its own unique features. Bitcoin is the most popular and widely used, but there are also altcoins such as Ethereum, Litecoin, and Ripple. Bitcoin is a decentralized digital currency, while altcoins are built on top of existing blockchain technology. Ethereum is a platform for decentralized applications, while Litecoin is a faster and more efficient version of Bitcoin. Ripple is a real-time gross settlement system. All of these cryptocurrencies differ in terms of their technology, purpose, and use cases.