Astro
Planted:
Astro is a site generator that has a React-like syntax, but allow for the embedding of other frameworks, like Svelte, into pages both at build time and in the client.
Initially it was just static, but it now support Server side rendering (SSR) and other dynamic functionality.
A majority of my content focused sites now are built using Astro, including this one.
My personal contribution to Astro as a project has been adding TOML Frontmatter support back in version 5.2 (technically released in the markdown-remark package v6.1.0)