A consolidated list of sites which provide ready to use UI Snippets for React / Bootstrap / Tailwind CSS
https://snippets.alexandru.so/ - Has animated buttons, input texts etc.
https://ui.aceternity.com/ - Great site with amazing components & animated elements
https://ui.ibelick.com/ - Collection of dark mode components (buttons, text, input, borders) and effects
https://bg.ibelick.com/ - Collection of backgrounds
https://react-tailwind-snippets.vercel.app/ - UI Template Layouts
https://www.creative-tim.com/bits/ - Contains snippets for almost everything.
https://tailwindcomponents.com/ - Snippets/Components submitted by users (Some are paid)
https://tailwindflex.com/ - Community built large component library wit 1400+ effects.
https://tailkit.com/free-ui-components - A few free UI components
https://freefrontend.com/tailwind-code-examples/ - Code examples for Tailwind
https://bbbootstrap.com/snippets - A collection of user contributed snippets
https://app.ui-snippets.com/ - Collection of toggles, buttons & text inputs (Vanilla CSS too)
https://ui-snippets.dev/ - Collection of components
https://www.designbombs.com/freebies/ - Collection of Templates with Bootstrap
If you know of any good sites or repos which may help/give insipiration/ideas please feel free to contribute. Fork the repo & create a Pull Request with the additions!