1. Bitcoin (BTC): The first and most widely recognized cryptocurrency, Bitcoin is a decentralized digital currency created in 2009 by an anonymous developer known as Satoshi Nakamoto.
2. Ethereum (ETH): Ethereum is a blockchain-based platform for developing decentralized applications and smart contracts. It was proposed in late 2013 by Vitalik Buterin.
3. Ripple (XRP): Ripple is an enterprise blockchain solution for cross-border payments and settlement. It is designed to enable banks to send money across borders quickly and cheaply.
4. Litecoin (LTC): Litecoin is an open source cryptocurrency that was created in 2011 by former Google engineer Charlie Lee. It is similar to Bitcoin but has faster transaction speeds and a larger supply.
5. Monero (XMR): Monero is a privacy-focused cryptocurrency that was launched in 2014. It is designed to keep transactions secure and untraceable, making it attractive to those looking for greater anonymity.
6. Dash (Dash): Dash is a cryptocurrency based on the Bitcoin protocol but modified for more speed and privacy. It was first released in 2014 and has become one of the most popular cryptocurrencies.