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.

albedo0

Automatic Hx Menu scans your content for heading tags and builds an in-page navigation with anchor links. 
You can also enable automatic numbering for your headings.
Shortcode: 
Use <code>[automatichxmenu]</code> in a post/page to insert the menu manually. In “Automatic & Shortcode” mode, the shortcode has priority.
Main features 
– “Back to top” links 
– Collapsible submenus 
– Automatic numbering for titles 
– Smooth scroll options (speed, offset) 
– Show on posts, pages or both 
– Enable/disable on the homepage 
– Many display options (alignment, width, margins, colors, borders, custom CSS)

Automatic Hx Menu

Automatically generate a navigation menu from the titles of a post or a page

ONet Header Linkifier vs Automatic Hx Menu