Spatie is one of the greatest Laravel package contributors, if not the greatest. The team has created about 250 packages that have been downloaded over 200 million times. "We think we have a very good workflow to produce readable, maintainable, and reliable packages. We want to share the knowledge we've built up over the years with you in our course Laravel Package Training."
Today, I found a few repositories I hadn't seen before. I may add to Folio, including their own Markdown parser package that wraps CommonMark, a code-highlighting package that wraps Shiki.js, and a package skeleton repository.