In the past few years, we have covered a bunch of useful table of contents plugins that help you give your long posts better organization. SimpleTOC is made for Gutenberg. It is a block that inherits the style of your theme. It parses your post content to retrieve the headings.
Adding a table of contents to your long posts manually can be a hassle. This plugin does a lot of the work for you. It doesn’t make your site bloated either and works with AMP plugins. It lets you disable the h2 heading of the block to add your own. This plugin is available as a free download.