CoinGecko is a crypto market data aggregator. It allows you to see current prices, market capitalizations, and trading volumes. On top of that, CoinGecko also lets you take a look at past historical data and make comparisons.
DefiLlama is an analytics portal that provides stats related to the Decentralized Finance industry. It gives visibility into indicators such as Total Value Locked and dominance, among others, and allows you to filter by chain, category, project, and a number of other parameters.