On the fiat -> crypto side, choices is pretty limited, usually what you can buy/sell were ETH, BTC and stables as they are more regulated on papers regarding these assets, platforms like remitano, localbtc and localethereum is pretty established, but you have to deal with local fiat fluctuations as crypto stick USD mainly.

Other alts is totally different stories, its the place where you can diving in danger in search of a coin that bring the greatest returns, over there its about how you buy/sell against BTC or stables. Most of the trading challenges take places here.