Jamie Dąbrowiecki

Headingo is a lightweight utility plugin that allows administrators to control which heading levels are available in the editor toolbar. This tool only works for websites using the Classic Editor.
These settings are applied to all users with editing permissions.
The configurable heading levels are:
<ul>
<li>Heading 1</li>
<li>Heading 2</li>
<li>Heading 3</li>
<li>Heading 4</li>
<li>Heading 5</li>
<li>Heading 6</li>
<li>Preformatted</li>
</ul>
This is especially useful for removing the Heading 1 (H1) option to prevent editors from mistakenly selecting it, as well as removing heading levels which are not required on your website.
This plugin is intended for websites that rely on the Classic Editor editing experience. It does not attempt to modify the Block Editor (Gutenberg), where heading availability is governed by editor and theme configuration (theme.json) by design. The Classic Editor plugin is required for this plugin to work (or a theme that allows you to switch to the Classic Editor without the plugin).
<h3>Classic Editor</h3>
The Classic Editor (TinyMCE) is fully supported. Selected heading levels and Preformatted can be hidden from the formatting dropdown while remaining available via keyboard shortcuts or pasted HTML. The Paragraph option is always available and cannot be toggled.
<h3>Block Editor (Gutenberg)</h3>
This plugin does not control heading levels in the Block Editor. Gutenberg does not currently provide a reliable API for plugins to override available heading levels, as these are controlled by editor and theme settings.

Headingo

Choose which heading levels are visible in the Classic Editor toolbar.

Vinod

Link to Headline is a WordPress plugin that automatically adds anchor link icons next to your heading elements (H2, H3, H4). When clicked, these icons copy the direct URL to that specific section to the clipboard, making it easy for readers to share precise parts of your content. Key Features: 
* Automatically detects and adds anchor links to headings 
* Copy-to-clipboard functionality with visual feedback 
* Configurable heading levels (H2, H3, H4) 
* Option to position icons on the left or right of headings 
* “Link Copied!” tooltip option 
* Exclude specific posts/pages from anchor link generation 
* Compatible with most themes and page builders
<h3>Upgrade to Link to Headline Pro</h3>
Supercharge your site navigation with our powerful Pro version! 
* Automatic Table of Contents (TOC): Automatically generate a “Table of Contents” from your headings to let users navigate long articles with ease. 
* Interactive TOC: The Pro TOC includes smooth scrolling, a collapsible box, and scrollspy (highlights the current section as you scroll). 
* More Heading Levels: Get support for H5 and H6 headings. 
* Manual Placement: Use the <code>[lthagp_toc]</code> shortcode to place your Table of Contents anywhere. 
* Priority Support: Get faster, dedicated support.
<a href="https://kudavoor.gumroad.com/l/link-to-headline-anchor-link-generator-pro" rel="nofollow ugc">Click here to learn more about the Pro version!</a>

Link to Headline – Anchor Link Generator

Automatically adds anchor links to headings, making it easy for readers to share specific sections of your content.

Headingo vs Link to Headline – Anchor Link Generator