No JS framework is prevalent in the Crystal community (like Laravel / Vue / Mix).
I use Preact / React and Vanilla JS. For the state management, I use Storux - State manager (home made). Some colleagues are happy with MobX
React is productive, as long as you keep its structure simple, without unnecessary overpatterning. I did some big projects with it, with several people. It scales well, remains simple and maintainable.
https://www.mint-lang.com looks great, but what stopped me from trying it is that there is no SSR, nor code splitting support (chunk file, lazy loaded). I hope to have the opportunity to test Mint one day.
Svelte.js looks nice also, I think I will test it on a small project.
The builder I use is vite.js. I used to use Webpack before, but Vite goes faster (based on Rollup and ES builder).