Altcoins, or alternative cryptocurrencies, offer a diverse range of investment opportunities beyond Bitcoin. With over 10,000 altcoins, investors can choose from various types, such as mining-based, pre-mined, and token-based. Popular altcoins like Ethereum, Litecoin, and Cardano provide innovative features and technologies. While altcoins offer growth potential and diversification, they also come with risks like volatility, liquidity issues, and regulatory uncertainty. Careful research and risk management are essential for navigating the altcoin market.