How does one know which altcoins come out recently and thus are trading pretty good? You can check coinmarketcap to see which coin has increased in price or decreased in price the most in last 24 hours or 7 days or month etc. But besides that, are there sites that show what coins will be released soon to the public? Thus by that i mean being able to buy from exchange like binance etc.
The best bet remains visiting regularly the most reliable platforms on line in the name of coinmarketcap and coingecko or installing the mobile versions of coinstats in your phone. These are all I use and it has been well efficient enough for me