What Cryptos can I buy on Kraken?

As a crypto enthusiast, I'm always looking for new opportunities to diversify my portfolio. Could you please elaborate on the cryptocurrencies available for purchase on Kraken? I'm particularly interested in knowing if they offer popular coins such as Bitcoin, Ethereum, and Litecoin, but I'm also curious about some of the more niche or emerging altcoins. Additionally, I'd like to understand if Kraken provides access to any stablecoins or decentralized finance (DeFi) tokens. Lastly, is there a specific process or requirement for purchasing cryptos on Kraken that I should be aware of? Your insights would be greatly appreciated.