Konrád Koller

Do you like to write long articles with many headers? Then this is the perfect plugin for you. This plugin will add a link next to your headers so your user can share your posts pointing to specific parts. Plus a smooth scroll script is also included which will make the overall experience even better.
The package contains a predefined style for Git-like link display but it is hardly recommend to change the style to fit your needs (and your design).
The plugin uses internal cache which may interfere with other cache plugins, if you experience anything strange feel free to contact the plugin author.

ONet Header Linkifier

For advanced users! Github-like header parser for your posts, pages and custom contents. Also lets you fetch TOC for any content.

elpresidento

Creates anchor links to heading tags in the content and displays them automatically at the top of the content, or allows for custom placement with tags or sidebar widget.
Features:
<ul>
<li>Has option to auto display anchor links to Heading tags in content.</li>
<li>Allows control of which content to auto display links.</li>
<li>Can disable plugin css to allow custom styles to be applied.</li>
<li>Has widget available for display</li>
<li>Insert custom title to display above links</li>
<li>Clears all traces from any excerpts displayed</li>
<li>Selection between numerically ordered and bulleted list </li>
<li>Auto Links indentation</li>
<li>qTranslate/mqTranslate support</li>
<li>Show “back to content” link next to heading</li>
</ul>
<h3>Known issues</h3>

Better Anchor Links

Creates anchor links to heading tags in the content and displays automatically at the top of the content, or allows for custom placement with tags.

ONet Header Linkifier vs Better Anchor Links