If you're looking for a static generator that makes it easier for you to create docs, you'll love Docsify. Unlike GitBook, it does not generate static HTML files. Instead, it loads and parses your Markdown files and displays them as a website.

Grammarly is a popular grammar and spell-checking tool that also provides suggestions for improving writing clarity and style. It can be used as a browser extension or standalone application.

Hemingway Editor is a writing tool that focuses on improving the readability of your text. It highlights complex sentences, excessive adverbs, and passive voice to help you create clear and concise content.

If you're looking for a framework to help you build your documentation site quickly, check out Hugo. It allows you to output your content in multiple formats, including JSON or AMP as well as provides shortcodes to simplify your Markdown files.