Yes, you can buy fundamentally strong coins from the Top 20 list at coinmarketcap. The advantage of buying the top coins means that they have enough liquidity and market cap. These strong coins have the tendency to recover more faster as compare to the shit coins.
Even if you want to buy new coins, first study the project and if you feel the potential, buy only with a limited amount. Do not invest thinking that project is good & price is less, so you can make 10x -50x. Greediness will only make you lose your money.