National and governmental websites, university websites, Kaggle, r/datasets, YouTube and Twitter APIs, papers with code website. These are some of my favorite places to find stuff

In a sense it is just copying and pasting from the web just in a different order, but I get that that is not your question. Something I would try is to use plagiarism checking sites online to see if there is an exact copy of your text online. If there is than you should be able to either attribute it to the right person or re write it a bit so it is not plagiarism