I do not know if there is any of such app but what I do is that I have several exchanges. All the exchanges will give a notification about the coin that they are about to list on their site. Some of them also have in-app notifications.

But the thing is if you do not have an exchange that a coin first want to be listed, no notification would be sent. Having like 10 exchanges can be helpful.

Some like Binance, Kucoin, Bybit, OKX and others always send notification about the coin that they are about to list.