Sami Keijonen

This plugin register a widget to display authors by role in a sidebar. You can choose whether to display author post count, biography or gravatar.
<h4>Usage</h4>
Go to Appearance >> Widgets. There you can find widget called Display Authors Widget. There are some settings in a widget.
<ul>
<li>Title: Set whatever title you want, or leave it blank to disable the title.</li>
<li>Role: Choose which role authors you want to display.</li>
<li>Display Post Count?: This displays the number of posts the author have published. This will only be shown if there are at least one post by author. The format 
is Author name ($number). </li>
<li>Display Author Bio?: If checked, this will display the author’s bio as set in their WordPress profile page.</li>
<li>Display Author Gravatar?: If checked, this will display the author’s gravatar.</li>
<li>Gravatar Size: This is the size of the gravatar image in pixels. Do not write px or pixels in this field. If you want gravatar size to be 50px, then write “50” in this field.</li>
<li>Gravatar Alignment: Choose whether you want to display gravatar on the left, right or no alignment at all.</li>
<li>Limit: This will allow you to set the number of authors that are displayed in the widget.</li>
</ul>

Display Authors Widget

Edward Caissie

Display various site statistics (read: counts) such as: posts, pages, categories, tags, comments, and attachments. Each site statistic can be toggled via a checkbox in the widget option panel. 
* Copyright 2012-2015 Edward Caissie (email : edward.caissie@gmail.com)
This program is free software; you can redistribute it and/or modify 
 it under the terms of the GNU General Public License version 2, 
 as published by the Free Software Foundation.
You may NOT assume that you can use any other version of the GPL.
This program is distributed in the hope that it will be useful, 
 but WITHOUT ANY WARRANTY; without even the implied warranty of 
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 
 GNU General Public License for more details.
You should have received a copy of the GNU General Public License 
 along with this program; if not, write to the Free Software 
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
The license for this software can also likely be found here: 
 http://www.gnu.org/licenses/gpl-2.0.html

BNS Site Data

Display various toggleable site statistics.

Display Authors Widget vs BNS Site Data