Writing tools sit on a spectrum between proofreading and ghostwriting, and the useful ones are at the proofreading end. A grammar checker that catches a real mistake is worth paying for; a tool that rewrites your paragraph into generic corporate prose is not, and will make your writing harder to distinguish from everyone else using the same tool. The listings here separate tools that improve your own sentences from tools that replace them. If you publish anything professionally, the two habits worth building are a plain-language pass and a read-aloud pass, and most of these tools automate one of the two. Where a tool has a strong free tier, that is noted, because for most people the free tier is genuinely enough and the paid upgrade mostly buys team features you do not need.
DeepL
Translation that reads like it was written in the target language.
Grammarly
Proofreading that catches more than a spellchecker.
Hemingway Editor
Highlights the sentences that are hard to read.
LanguageTool
Open-source grammar checking, including self-hosted.
Otter.ai
Meeting notes that write themselves, mostly.
ProWritingAid
A style checker that explains why a sentence is weak.
QuillBot
Paraphrasing tool for rewording, with a useful grammar check.
Sudowrite
An AI writing partner built for fiction, not marketing copy.
Ulysses
A distraction-free editor for people who write for a living.
Scrivener
Long-form writing software built around a binder of scenes.
Zotero
Free reference manager that keeps citations and PDFs together.
Final Draft
The screenwriting format that production offices expect to receive.
Vellum
Book formatting for ebook and print, previewed as you work.
Rev
Human transcription and captions priced by the audio minute.
No tools in this category match that filter.