As of December 20, 2024, the top 10 cryptocurrencies by market capitalization are:

1. Bitcoin (BTC): The first and most well-known cryptocurrency, often referred to as digital gold.

2. Ethereum (ETH): A decentralized platform that enables smart contracts and decentralized applications (dApps).

3. Tether (USDT): A stablecoin pegged to the US dollar, commonly used for trading and as a store of value.

4. XRP (XRP): A digital payment protocol and cryptocurrency aimed at facilitating fast and low-cost international money transfers.

5. BNB (BNB): The native cryptocurrency of the Binance exchange, used to pay for transaction fees and participate in token sales.

6. Solana (SOL): A high-performance blockchain platform designed for decentralized applications and crypto-currencies, known for its fast transaction speeds.

7. Dogecoin (DOGE): Initially created as a joke, this cryptocurrency has gained popularity due to its active community and widespread adoption.

8. USD Coin (USDC): Another stablecoin pegged to the US dollar, used for trading and as a digital dollar.

9. Cardano (ADA): A blockchain platform focused on security, scalability, and sustainability for the development of decentralized applications.

10. TRON (TRX): A blockchain-based operating system and decentralized platform for content sharing and entertainment applications.

These rankings are based on data from Crypto.com and Slickcharts.

Please note that the cryptocurrency market is highly volatile, and rankings can change rapidly. It's essential to conduct thorough research before making any investment decisions.