Dhaval Kasavala

This plugin allow you display your site all user and their avatar which is selectable what you attach with post.

Contributors role with post

This is simple plugin for contributers with post.

Jesper van Engelen

Ever since the WordPress roles and capabilities system implemented in WordPress verion 2.0 back in 2005, there has been no easy way to implement a user hierarchy.
With the User Hierarchy plugin, you can control which user roles can edit which other user roles. For example, you can add a new user role called “Manager” that can view all users, but only create and edit users with the “Author” user role. This plugin gives you full control over your user management, even when you are using a complex role hierarchy.

User Hierarchy

Control user management on a per-role basis. Allow users of a certain role to only add, edit or delete users from specific other roles.

Contributors role with post vs User Hierarchy