Library

The right question is: is there added value in reinventing the wheel? (button, form controls, badge, card, spinner, modal...). The existing wheels will probably ride better than yours.

I would go with vanilla Bootstrap (just the Sass part, not the JS part).

Bootstrap

Bootstrap CSS utilities are very nice: same principles as Tailwind CSS.

Neutral look
Well maintained since 2011: twbs/bootstrap#23586
Well documented
Well tested
Very well coded and thought: https://github.com/twbs/bootstrap/blob/v5.2.3/scss/_buttons.scss
Comes with CSS utilities like Tailwind CSS: https://getbootstrap.com/docs/5.2/utilities/
Not bloated contrary to popular believe: https://getbootstrap.com/docs/5.2/customize/sass/#importing
The most popular

Small example app: https://github.com/tkrotoff/MarvelHeroes (React with hooks, Bootstrap, TypeScript, React Router, Jest)

https://www.npmtrends.com/@chakra-ui/core-vs-@material-ui/core-vs-antd-vs-bootstrap-vs-bulma-vs-react-bootstrap-vs-tailwindcss-vs-@mui/material

https://star-history.com/#twbs/bootstrap&tailwindlabs/tailwindcss&mui/material-ui&ant-design/ant-design&jgthms/bulma&react-bootstrap/react-bootstrap&chakra-ui/chakra-ui&Date

https://insights.stackoverflow.com/trends?tags=bootstrap-5%2Cbootstrap-4%2Creact-bootstrap%2Cmaterial-ui%2Cantd

Tailwind CSS

You will read only good things about it on Reddit, Twitter... people love it. See it as lower level compared to Bootstrap, it does not come with a UI: you have to code it yourself (you could re-create Bootstrap using it). Fits perfectly if you need to code your own design system.

React Bootstrap/Reactstrap

Use React Bootstrap/Reactstrap only when needed (collapse for example): one layer less to learn and maintain. Does not bring that much value (<button className="btn btn-primary"> vs <Button variant="primary">) + you will be able to update Bootstrap without waiting for React Bootstrap/Reactstrap to catch up.

Material-UI

Very popular right now (and well done, well maintained, well tested and documented, full of features...) but kind of bloated: JSS, generates a big and ugly DOM, more concepts to grasp...

Bulma

Too minimalist, quite verbose (is-three-quarters, is-three-fifths, is-primary, has-icons-left...), with very limited utility classes.

Chakra UI

Less popular than Material-UI, too new and does not come with unit tests: https://github.com/chakra-ui/chakra-ui/tree/v0/packages/chakra-ui/tests. I would never invest time using a UI library that is not properly tested.