As of my knowledge cutoff in September 2021, there were thousands of cryptocurrencies in the world. However, it's important to note that the cryptocurrency market is highly dynamic, and new cryptocurrencies can emerge while others may become inactive or lose value over time.
Some of the well-known cryptocurrencies include Bitcoin (BTC), Ethereum (ETH), Ripple (XRP), Litecoin (LTC), Bitcoin Cash (BCH), and many more. Additionally, there are numerous altcoins (alternative cryptocurrencies) that serve various purposes and cater to different communities and industries.
Since my information is not up-to-date, I recommend consulting reliable cryptocurrency sources or market data platforms for the most current and accurate information regarding the number of cryptocurrencies available today.