I have never blacklist any altcoins, because I use to carry out my personal research before approaching any altcoin in the market and it has been helping me not to invest in a wrong altcoins that will cause me losses, and there is nothing will make me to invest in anyhow altcoins in the market. If you are part of potential altcoins investors, you will always be in the winning side OP, because they always invest their capital on ten top altcoins which they use to increase alongside with Bitcoin to caused their investors to experience huge amount of income. Anything that will make you experience losses in your altcoins investment, stay away from such altcoins, because they will make you regret for making such altcoins your choice and you will blacklist them, because you don't want to fall victim again.