The HTML <div> element (or HTML Document Division Element) is the generic container for flow content, which does not inherently represent anything. It can be used to group elements for styling purposes (using the class or id attributes), or because they share attribute values, such as lang. It should be used only when no other semantic element (such as <article> or <nav>) is appropriate.
The HTML <ol> Element (or HTML Ordered List Element) represents an ordered list of items. Typically, ordered-list items are displayed with a preceding numbering, which can be of any form, like numerals, letters or Romans numerals or even simple bullets. This numbered style is not defined in the HTML description of the page, but in its associated CSS, using the list-style-type property.
The HTML <pre> element (or HTML Preformatted Text) represents preformatted text. Text within this element is typically displayed in a non-proportional ("monospace") font exactly as it is laid out in the file. Whitespace inside this element is displayed as typed.
CSS Generated Content is a module of CSS that defines how to add content to an element.
The HTML <area> element defines a hot-spot region on an image, and optionally associates it with a hypertext link. This element is used only within a <map> element.
The HTML <blockquote> Element (or HTML Block Quotation Element) indicates that the enclosed text is an extended quotation. Usually, this is rendered visually by indentation (see Notes for how to change it). A URL for the source of the quotation may be given using the cite attribute, while a text representation of the source can be given using the <cite> element.
The HTML <dd> element (HTML Description Element) indicates the description of a term in a description list (<dl>) element. This element can occur only as a child element of a description list and it must follow a <dt> element.
The HTML <dl> element (or HTML Description List Element) encloses a list of pairs of terms and descriptions. Common uses for this element are to implement a glossary or to display metadata (a list of key-value pairs).
The HTML <dt> element (or HTML Definition Term Element) identifies a term in a definition list. This element can occur only as a child element of a <dl>. It is usually followed by a <dd> element; however, multiple <dt> elements in a row indicate several terms that are all defined by the immediate next <dd> element.
The HTML <figcaption> element represents a caption or a legend associated with a figure or an illustration described by the rest of the data of the <figure> element which is its immediate ancestor which means <figcaption> can be the first or last element inside a <figure> block. Also, the HTML Figcaption Element is optional; if not provided, then the parent figure element will have no caption.
The HTML <figure> element represents self-contained content, frequently with a caption (<figcaption>), and is typically referenced as a single unit. While it is related to the main flow, its position is independent of the main flow. Usually this is an image, an illustration, a diagram, a code snippet, or a schema that is referenced in the main text, but that can be moved to another page or to an appendix without affecting the main flow.
The HTML <hr> element represents a thematic break between paragraph-level elements (for example, a change of scene in a story, or a shift of topic with a section). In previous versions of HTML, it represented a horizontal rule. It may still be displayed as a horizontal rule in visual browsers, but is now defined in semantic terms, rather than presentational terms.
The HTML Inline Frame Element (<iframe>) represents a nested browsing context, effectively embedding another HTML page into the current page. In HTML 4.01, a document may contain a head and a body or a head and a frameset, but not both a body and a frameset. However, an <iframe> can be used within a normal document body. Each browsing context has its own session history and active document. The browsing context that contains the embedded content is called the parent browsing context. The top-level browsing context (which has no parent) is typically the browser window.
The HTML <img> element represents an image in the document.
The HTML <li> element (or HTML List Item Element) is used to represent an item in a list. It must be contained in a parent element: an ordered list (<ol>), an unordered list (<ul>), or a menu (<menu>). In menus and unordered lists, list items are usually displayed using bullet points. In ordered lists, they are usually displayed with an ascending counter on the left, such as a number or letter.
The HTML <main> element represents the main content of  the <body> of a document or application. The main content area consists of content that is directly related to, or expands upon the central topic of a document or the central functionality of an application. This content should be unique to the document, excluding any content that is repeated across a set of documents such as sidebars, navigation links, copyright information, site logos, and search forms (unless the document's main function is as a search form).
The HTML Embedded Object Element (<object>) represents an external resource, which can be treated as an image, a nested browsing context, or a resource to be handled by a plugin.
The HTML <p> element (or HTML Paragraph Element) represents a paragraph of text. Paragraphs are usually represented in visual media as blocks of text that are separated from adjacent blocks by vertical blank space and/or first-line indentation. The paragraph must be closed at end of the text "<p> text </p>" are requried to put the text between the paragraph. Paragraphs are block-level elements.
The HTML <param> Element (or HTML Parameter Element) defines parameters for <object>.
The HTML <ul> element (or HTML Unordered List Element) represents an unordered list of items, namely a collection of items that do not have a numerical ordering, and their order in the list is meaningless. Typically, unordered-list items are displayed with a bullet, which can be of several forms, like a dot, a circle or a squared. The bullet style is not defined in the HTML description of the page, but in its associated CSS, using the list-style-type property.