I need some advice, I had some crypto a few years ago and then sold it and made some good profits and I am now planning to buy some crypto once again and I admit that I am outdated on the crypto world right now. Can someone give a brief explanation of what DeFi is and what are your top 5 coins/tokens and where do you usually trade it. Thanks! 
I can not give you suggestions about what DeFi token you should buy because I am afraid to provide you with the wrong token. But for the top 5 coins, I think you can take a look at ethereum, bnb, litecoin, dot, and atom. But I am sure that there are many other altcoins that you can analyze to find the coin. After all, you do not have to follow my suggestion before analyzing it by yourself because I might be wrong in the suggestion.