Discourse uses a free set of SVG icons from Font Awesome ({{i18n "styleguide.sections.icons.full_list"}}).

Plugins and themes can add SVG icons to the SVG spritesheet, or replace existing icons entirely.

• How to use SVG icons in your plugin or theme
• How to replace Discourse's default icons in a theme

By default, all icons have the

.d-icon

class applied along with a class containing the name of the icon (e.g.,

.d-icon-link

)