Welcome To Custom Logic Innvation

Plugins and building blocks
For SEO fields, the most relevant public plugin I found is sanity-plugin-seo, which is described as adding built-in SEO features such as meta tags and structured data. I also found sanity-plugin-seo-pane, but that repo says it is deprecated and can no longer be recommended, so I would avoid building on that one.

For tables, there are already public plugins: @sanity/table and Sanity Plugin STL Table, and the STL Table page says it supports advanced tables with links, buttons, headers, footers, and cell attributes. For internal links, a Sanity Community answer shows the common pattern of storing an internal link as a reference and resolving it with reference->slug, which is useful for your internal links + anchor text requirement.