21st.dev

This is the widest React/Tailwind surface in the index -- reach for it when shadcn/ui core has no answer, especially for animated heroes, shader and gradient backgrounds, and AI chat blocks. Install with the 21st MCP (npx @21st-dev/cli@latest install <client> --api-key <key>; the old @21st-dev/magic package still proxies, but old Magic keys were reset) so the editor can search and insert in one step. Two cautions: it is community-submitted, so quality, accessibility, and license vary per author and you must read the source before shipping; and copying code or prompts needs a paid Builder seat, so an unauthenticated agent can browse but not extract.

Why it is here. It is the de facto public square for shadcn-compatible components, and the only one at this scale with a first-party MCP that plugs the whole catalog into an editor.