We also often require content for link building campaigns and PBN posts. This is a whole different story as for this purpose, we need to come up with sometimes thousands of unique articles for just one campaign. If you’re using automated link building software like RankerX of GSA SER, you know that sourcing original content for your campaigns is probably the most difficult part.
Seriously noone has mentioned Unique Article Wizard? Check it out it blows the other 30 or so article writers I've tried out of the water. It contains a synonym database updated by users so the synonyms actually make sense and are available for entire phrases as well. There is no magic pill that lets you click a button and bam you have a new unique article. That doesn't and will never exist so stop lookin if you are(or squander your hard earned $ on failware)!
It is also very helpful for people who struggle with the English language in general and writing in particular. A free article spinner or paraphrase tool makes it easier for them to get new content with minimal effort. The quality of content created with article rewriter is close to human written content if not equally good. To ensure the quality, you can edit content to fix any errors.