container : Containers are a fundamental building block of Bootstrap that contain, pad, and align your content within a given device or viewport.

row : Rows are wrappers for column each column has horizontal padding.

col : col class in bootstrap is build on grid's flexbox structure, it is used to create equal or unequal columns.

form :Bootstrap forms class simplifies the process of styling and alignment of form controls like labels, input field, textbox, buttons.

input : input group easily extend form controls by adding text, buttons, or button groups on either side of textual inputs.

navbar : With Bootstrap, a navigation bar can extend or collapse, depending on the screen size. A standard navigation bar is created with the . navbar class, followed by a responsive collapsing class: . navbar-expand-xl|lg|md|sm (stacks the navbar vertically on extra large, large, medium or small screens).

button : Use Bootstrap's custom button styles for actions in forms, dialogs, and more with support for multiple sizes, states, and more

carousel : The carousel is a slideshow for cycling through a series of content, built with CSS 3D transforms and a bit of JavaScript. It works with a series of images, text, or custom markup. It also includes support for previous/next controls and indicators.

carousel-item : carousel item allows to style the content of carousel.

icons : Bootstrap Icons is a growing library of SVG icons that are designed by @mdo and maintained by the Bootstrap Team.

list-group : List groups are a flexible and powerful component for displaying a series of content. Modify and extend them to support just about any content within.