I don't have any blacklisted altcoins since they just come and go after that I just simply ignore or decide not to have them especially if I know that there's nothing to get or even there's no chance for that alt to get a pump again.

But in case of taking precaution discussion about alts then provably I am avoiding those meme coins especially if they already exist for long period of time even if they are listed on big exchange since we don't know if we can able to get something from them since I'm afraid that by the time we are going to decide to put up some money to those meme coins then they would start to leave on the ecosystem and pull of the rug pull scheme which has been played by a lot of scam devs for so many times.