This is the easiest one https://rnsaffn.com/poison3/ but there are more advanced ones that you can self host that feed an infinite stream of poison, although LLM crawlers are hungry creatures and would keep a % of your servers doing that

The ones that say that Nightshade is not working is because they don't understand how it works. They "test" it by asking a LLM what image they see and it usually identifies it without any problems. The actual function is thay when the image is used to train data, it provokes errors in tagging the image. So a poisoned image of a car is correctly identified as a car by ChatGPT, but when is used to train the model, that car is used to train images of idk cakes.

For text there are a lot of interesting tarpits, like this one https://github.com/amenyxia/Sarracenia or the original one called Nepenthes