As you know, each framework has its advantages and disadvantages, you have to choose wich your own framework you will use for your projects after determining requirements & analysis, in other words, suit your needs, CSS frameworks are very incredible because they make your website very responsive and practical .
Backed by Twitter, Bootstrap 4 is the most popular front-end framework for developing responsive, mobile projects on the web.
Alerts provide feedback messages to user,Bootstrap offers differents classes specialy for alerts for example, .alert-primary,alert-secondary,alert-success,alert-danger,alert-warning,alert-info,alert-light,alert-dark .
These classes are available also for links.
Bootstrap allows different classes for custom button styles for actions in forms, dialogs and more with support for multiple sizes, states
<button type="button" class="btn btn-outline-primary">Primary</button>
<button type="button" class="btn btn-outline-secondary">Secondary</button>
<button type="button" class="btn btn-outline-success">Success</button>
<button type="button" class="btn btn-outline-danger">Danger</button>
<button type="button" class="btn btn-outline-warning">Warning</button>
<button type="button" class="btn btn-outline-info">Info</button>
<button type="button" class="btn btn-outline-light">Light</button>
<button type="button" class="btn btn-outline-dark">Dark</button>
A card is a bordered box with some padding around content, it offers many options for headers, footers, content, colors,etc.
Bulma is an open source CSS framework based on flexbox.
Bulma grid is built with Flexbox for achieving flexible layout with same size columns.
Semantic UI is a front end framework like Bootstrap and Bulma, Semantic UI offer components more interaction than Bootstrap, in addition, these components have richer behaviors and extensibility
Semantic UI is very easy to use compared with other frameworks.
Semantic uses behaviors that trigger functionality.
Based on NodeJS and Gulp , they are very easy to install wich facilitates installation on developers.
Materialize CSS is a front end framework based on Material Design, is used to create responsive websites and provides rich layouts, animations, many powerful UI.
Materialize is by design very minimal and flat it is designed considering the fact that it is much easier to add new CSS rules than to overwrite the existing CSS rules. It supports shadows and bold colors. The colors and shades remain uniform across various platforms and devices
CSS frameworks focused on responsive web design aspects, otherwise, these CSS frameworks cover all area of responsive web development, a good CSS framework may contain many options like user interface, layouts, grid system, responsive tables, etc.
On the other hand, all CSS frameworks are best and powerful, but choosing any one of them depends on what you need.