Andrew Ozz

Excerpt Editor provides a convenient place for creating and editing all excerpts. It can also add custom excerpts for pages (not possible without a plugin). Features: auto-creating excerpts when publishing new Posts and Pages, displaying customisable excerpts from the content for posts without an excerpt, appending excerpts from the latest posts to each Post or from the sub-pages to each Page, replacing the content for all archive and tags pages with excerpts (eliminates content duplication for SEO).
The excerpts can be used in the RSS feed, displayed on the Home or Archive pages and/or used for meta descriptions. The excerpts can be in any language supported by WordPress and the plugin contains .pot file to facilitate translations.

Excerpt Editor

Quick edit or create excerpts for both Posts and Pages, auto-generate and append excerpts or replace the content with excerpts.

J0SiE

Created to help those people who don’t like to edit code in template files (or are too lazy to do that). 
Just activate the plugin and it will automatically show the_excerpts in your homepage, archives and search results. 
It tries to display your custom excerpt text and if it doesn’t find it it will show an automatically generated excerpt. 
You can also define excerpt length, custom read more link and attach a thumbnail.

Auto Excerpt everywhere

Thanks to author for creating this plugin. 
It's works out of box. And working fine at WordPress Version 4.6.1


Works out of the box on WP Version 4.6.1

The plugin automatically displays excerpts instead of full post contents in your blog. Custom excerpts and generated excerpts supported.

Excerpt Editor vs Auto Excerpt everywhere