I was the original author of and still sometimes contribute code to Yoast SEO and its addons. Next to that, I maintain a few simple WordPress plugins myself:
WordPress’ comment system is incomplete. This plugin adds a lot of nifty little tricks to make comments on WordPress a lot more manageable.
XML sitemaps for PDFs
If your site has a lot of PDFs, this add-on to Yoast SEO is what you need to get them indexed.
I actively contribute to other projects, including the software of some of the companies in our investment portfolio. To read more about that, see either my about page, or read about Emilia Capital.