Bootstrap is the most popular CSS front-end framework. It is amazing in its capabilities, but there are other frameworks that might be good enough for you. Here are 10 of the best alternatives that you should definitely try.
1. Foundation
A Foundation framework for any device, medium, and accessibility. Foundation is a family of responsive front-end frameworks that make it easy to design beautiful responsive websites, apps and emails that look amazing on any device. Foundation is semantic, readable, flexible, and completely customizable. You cat get templates for your website: https://get.foundation/templates.html
2. Uikit (getuikit.com)
A lightweight and modular front-end framework for developing fast and powerful web interfaces.
This framework contains hundreds of components, buttons, forms, icons, modals and other UI components for your website. Full documentation of this framework You can see on this website: https://getuikit.com/docs/introduction
3. Materialize (materializecss.com)
A modern responsive front-end framework based on Material Design. Material design is a language created by Google that combines traditional design methods with innovation and technology.
You can simple start using Materialize, just go to the page: https://materializecss.com/getting-started.html and download Materialize framework to your project.
4. Metro (themes.org.ua)
Metro 4 is a component library for developing sites with HTML, CSS, and JS. Quickly prototype your ideas or build your entire app with responsive grid system, extensive prebuilt components, and powerful plugins.
Metro 4 developed to build websites in Windows Metro Style and include general styles, grid, layouts, typography, 100+ components and routines, 600+ built-in icons.
Metro 4 is an open-source and has an free dual licensing model.