srcoley

This wigetized plugin shows the gravatar and info of the most recently active authors of your blog. The author with the most recent post will be displayed first, the author with the second latest will be displayed second, and so on.
Awesome Authors allows you to select ‘Sticky Authors.’ These authors will be displayed at the front of the list no matter how long ago their latest post was published. Conversely, you can select authors to be ‘Excluded Authors.’ These authors will never be displayed in the list no matter how many posts they have or how recently their last post was published. You can also set a minimum post requirement. If you set this to, let’s say 10, then only authors with 10 or more published posts will be displayed on the Author Bar. Some of the other options include gravatar display size, and how many authors overall to display.

Awesome Authors

This wigetized plugin shows the gravatar and info of the most recently active authors of your blog.

Gianluigi Filippelli

<a href="https://wordpress.org/plugins/co-authors-plus/" rel="ugc">Co-Authors Plus</a> is one of the most useful plugin for multiple authors blogs. This plugin add a widget to add users’ avatars to post also for guest authors and for posts with multiple authors. 
You can also add avatars with a shordcode [blog-post-coauthors]. 
The plugin add also a slider in order to show user’s profile. If you want change the style, you can modify blog-spoiler.css file in the plugin folder.

Co-Authors Widget

The plugin add a widget and a shortcode in order to show authors of an article. It is compatible with Co-Authors Plus.

Awesome Authors vs Co-Authors Widget