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.
I doubt if there are newly-out coins that are immediately listed on Binance. If you want altcoins that have just received the nod of Binance, you better follow the news from Binance themselves. They will release such.
Anyway, coinmarketcap is one option. But if you really want to know which coins will be released soon, you may have to check at the Announcement thread of this forum, under the alternate cryptocurrencies. These are new projects whose coins have yet to hit the exchanges.