List of free meta stuff for developerππ½
If you're looking for all programming tools around meta (not just free). Check this page List of meta Programming Tools

Web Code Tools
The ultimate web code generators. Generate HTML, CSS, JSON-LD, Twitter Cards, Open Graph and more! No coding skills required.
Tag: html, css, JSON, meta

Meta Tags
With Meta Tags you can edit and experiment with your content then preview how your webpage will look on Google, Facebook, Twitter and more!
Tag: meta, SEO