<a href=https://github.com>GitHub</a>
<a href=https://css-tricks.com>CSS-Tricks</a>
<a href=https://codepen.io>CodePen</a>

a[href^="http"] {
  padding-left: 19px;
  background-size: 16px 16px;
  background-repeat: no-repeat;
  background-position: left center;
}
a[href*="github.com"]{
  background-image: url(https://www.google.com/s2/favicons?domain=github.com);
}
a[href*="css-tricks.com"]{
  background-image: url(https://www.google.com/s2/favicons?domain=css-tricks.com);
}
a[href*="codepen.io"]{
  background-image: url(https://www.google.com/s2/favicons?domain=codepen.io);
}

a  {
  display: block;
  margin: 10px;
  text-decoration: none;
}