Очень хорошие примеры на чистом бутсрапе
https://mdbootstrap.com/plugins/jquery/chat/
https://mdbootstrap.com/education/bootstrap/
https://mdbootstrap.com/education/
https://getbootstrap.com/docs/5.3/examples/
https://ui.shadcn.com/docs/components
http://code.makery.ch/library/more-html-css/javascript-bootstrap/
Over 170 responsive design blocks ready to be used in your web or mobile apps
Offical patterns
https://startbootstrap.com/template-categories/all/
https://colorlib.com/wp/free-bootstrap-4-website-templates/
https://startbootstrap.com/themes/landing-pages/
https://www.os-templates.com/free-website-templates
https://wrapbootstrap.com/
https://html-templates.info/portfolio-html-templates/nebolshoy-shablon-sayta-portfolio
https://html2pug.now.sh/
ArchitectUI HTML Dashboard Free
Бесплантые хостинги
https://vercel.com
Демо апи
https://www.thecocktaildb.com