pyko

A simple plugin that allows you to modify the link that is displayed when you use the <!–more–> feature. Also lets you remove the anchor link to turn off the jumping behaviour. You can also choose to have the more link open in a new window/tab.
You can choose to have just plain text, or also include the post’s title. If you chose to include the title, you can limit the number of characters/words that are displayed in the title. Also allows you to add ellipsis (…) to the title if it has been truncated. All the options can be found in “More Link” tab under “Options” in admin page.

macha795

Add an article headline list to the post edit screen. 
Click the title heading to move to the heading position in the editing area.
You can always display the headline list in the screen by pressing the float button.
Only ClassicEditor is supported. Gutenberg is not supported yet.
<h3>Arbitrary section 1</h3>

EditorHeadlineJump

Add a heading list to the post edit screen. Click on the heading to move to the edit position.

More Link Modifier vs EditorHeadlineJump