pflonk

This plugin allows you to pass content to any sidebar from the page without using userdefined fields. Therefore it is possible to use the WYSIWIG-editor of your choice.
How it works: 
This plugin comes with a new enclosing shortcode [sidebar_content][/sidebar_content] where you can place any content, you want to have displayed in the sidebar. You will be able to use other shortcodes within this shortcode to use galleries, videos or any other stuff in the sidebar of your choice.
Additionally there will be a new widget which you can insert into the sidebar you want to have the content displayed. 
If you would like to pass content to an existing sidebar, there is another possibility using the [insert_sidebar_content] shortcode in any place you want. You are able to pass an id and/or a class to that content, to be able to style it with css as you like. This happens by simply adding: 
[insert_sidebar_content id=”yourID” class=”yourClass”] to the shortcode. You can of course use just one or none of them. If you do not specify any custom class or id, there will be a standard class and id called “insert_scfs” applied to the content, wrapped in a div.
<h3>Features</h3>
<ol>
<li>Widget</li>
</ol>
<ul>
<li>optional title (if empty, no tag will be generated)</li>
<li>optional title tag (default h3)</li>
<li>optional title tag CSS-classes</li>
<li>optional content-wrapper tag (default div)</li>
<li>optional CSS-classes for content-wrapper tag</li>
<li>optional CSS-id for content-wrapper tag</li>
<li>default values for every of the above possibilities</li>
</ul>
<ol>
<li>Shortcodes</li>
</ol>
2.1 Content-Enclosement
<ul>
<li>[sidebar_content]CONTENT[/sidebar_content] for use on any page</li>
</ul>
2.2 Widget-Display
<ul>
<li>[insert_sidebar_content id=”yourID” class=”yourClass”] to display the content from the [sidebar_content]-Shortcode in any widget you like</li>
<li>applicable id and classes</li>
</ul>
You will find further support on http://dev.offensichtlich.net
<h3>Thanks</h3>
Thanks to the authors that provided information about how to implement this simple little function that I just put together:
Ryan Bosinger 
http://www.ryanbosinger.com/boztown/2013/03/07/wordpress-custom-content/
1st-tec.de 
http://www.tipps.1st-tec.de/wordpress/39-wordpress/sidebar-widgets/152-eigene-widgets-fuer-die-sidebar-erstellen.html

Sidebar-Content from Shortcode

This Plugin enables passing content to any sidebar from the page without using userdefined fields. Therefore it is possible to use the WYSIWIG-editor  …

Freemius

DEV Institute

Joachim Jensen

<h3>Content Aware Sidebars is the #1 WordPress Sidebar Plugin</h3>
You can optimize conversion rates, boost on-site SEO, upsell products, and much more by displaying different widget areas on different conditions.
Create tailored widget areas in seconds. No widget logic coding required.
<h3>Show or Hide Widgets on Any Page (Yes, any)</h3>
Replace your theme sidebars on different conditions, or insert widget areas with shortcodes. The following Display Conditions are available out of the box:
<ul>
<li>Posts, Pages & Custom Post Types</li>
<li>Content with Tags, Categories, or Custom Taxonomies</li>
<li>Content written by select Authors</li>
<li>Page Templates</li>
<li>Blog Page & Post Type Archives</li>
<li>Author Archives</li>
<li>Taxonomy Archives</li>
<li>Front Page, Search Results, 404 Not Found Page</li>
<li>bbPress Profiles, Forums & Topics</li>
<li>BuddyPress Profile Sections</li>
<li>Languages (Polylang, qTranslate X, TranslatePress, Transposh, Weglot, WPML)</li>
<li>Pods Pages</li>
</ul>
<blockquote>
You can even combine conditions in any way you like! E.g. target all posts in a select category and written by a specific author.
</blockquote>
<h3>Add Unlimited Sidebars & Widget Areas</h3>
Create a post sidebar, a page sidebar, a category sidebar, or any custom sidebar you need – no coding required. CAS will never slow down your site, even if you create a lot of custom sidebars and conditions.
<blockquote>
Sidebars – Quick Select© lets you add or select widget areas directly when editing a post or page.
</blockquote>
<h3>Schedule & Disable Custom Sidebars</h3>
In the All-in-one Sidebar Manager you just pick a start and end date for when widget areas should be displayed, and CAS will take care of the rest.
<blockquote>
1-Click Sidebar Activation© lets you activate or deactivate widget areas instantly.
</blockquote>
<h3>The Most User-friendly Widget Manager</h3>
When adding new widgets to sidebars, Live Search will find widgets instantly, and the smart split-screen makes it a joy to manage a lot of widgets and sidebars.
<blockquote>
The Enhanced Widget Manager adds the signature turquoise line to easily identify custom sidebars.
</blockquote>
<h3>Sidebar Plugin Integrations & Support</h3>
CAS autodetects Custom Post Types and Taxonomies created by any plugin or theme. Built-in support for some of the most popular WordPress plugins means that you e.g. can create WooCommerce sidebars for select products or BuddyPress sidebars for your members.
<ul>
<li><a href="https://dev.institute/wordpress-sidebars/bbpress/?utm_source=readme&utm_medium=referral&utm_content=integration&utm_campaign=cas" rel="nofollow ugc">bbPress</a></li>
<li><a href="https://dev.institute/wordpress-sidebars/buddypress/?utm_source=readme&utm_medium=referral&utm_content=integration&utm_campaign=cas" rel="nofollow ugc">BuddyPress / BuddyBoss</a></li>
<li><a href="https://dev.institute/wordpress-sidebars/easy-digital-downloads/?utm_source=readme&utm_medium=referral&utm_content=integration&utm_campaign=cas" rel="nofollow ugc">Easy Digital Downloads</a></li>
<li><a href="https://dev.institute/wordpress-sidebars/multilingual-plugins/?utm_source=readme&utm_medium=referral&utm_content=integration&utm_campaign=cas" rel="nofollow ugc">qTranslate X</a></li>
<li><a href="https://dev.institute/wordpress-sidebars/pods/?utm_source=readme&utm_medium=referral&utm_content=integration&utm_campaign=cas" rel="nofollow ugc">Pods</a></li>
<li><a href="https://dev.institute/wordpress-sidebars/multilingual-plugins/?utm_source=readme&utm_medium=referral&utm_content=integration&utm_campaign=cas" rel="nofollow ugc">Polylang</a></li>
<li><a href="https://dev.institute/wordpress-sidebars/multilingual-plugins/?utm_source=readme&utm_medium=referral&utm_content=integration&utm_campaign=cas" rel="nofollow ugc">TranslatePress</a></li>
<li><a href="https://dev.institute/wordpress-sidebars/multilingual-plugins/?utm_source=readme&utm_medium=referral&utm_content=integration&utm_campaign=cas" rel="nofollow ugc">Transposh Translation Filter</a></li>
<li><a href="https://dev.institute/wordpress-sidebars/woocommerce/?utm_source=readme&utm_medium=referral&utm_content=integration&utm_campaign=cas" rel="nofollow ugc">WooCommerce</a></li>
<li><a href="https://dev.institute/wordpress-sidebars/multilingual-plugins/?utm_source=readme&utm_medium=referral&utm_content=integration&utm_campaign=cas" rel="nofollow ugc">Weglot</a></li>
<li><a href="https://dev.institute/wordpress-sidebars/multilingual-plugins/?utm_source=readme&utm_medium=referral&utm_content=integration&utm_campaign=cas" rel="nofollow ugc">WPML</a></li>
</ul>
<h3>Customize Your Widget Areas Your Way</h3>
Without writing any code, you can modify the HTML and CSS classes of widget areas, widgets, and widget titles. You get full control over the look and feel of your sidebars and widget areas, no matter what theme you use.
<blockquote>
Sidebar Visibility lets you elegantly hide any widget area for logged-out users.
</blockquote>
<h3>Complete control over your WordPress widget areas</h3>
<a href="https://dev.institute/wordpress-sidebars/?utm_source=readme&utm_medium=referral&utm_content=title&utm_campaign=cas" rel="nofollow ugc">Upgrade to Content Aware Sidebars Pro</a> and get these additional powerful features:
<ul>
<li>Totem – Smart Floating Button 
Like the button you may have seen by Intercom or Helpscout, only this is for all your widgets</li>
<li>Sticky Sidebars & Widget Areas 
Make any sidebar or widget area sticky without hurting site performance. No jQuery and no bloat</li>
<li>Widget Areas after Paragraphs 
Display a widget area after a specific number or percentage of paragraphs in your content</li>
<li>Even More Display Conditions
<ul>
<li>Advanced Custom Fields data</li>
<li>Meta Box data</li>
<li>URLs + wildcards</li>
<li>Referrer URLs</li>
<li>Date Archives & Content by publish date</li>
<li>BuddyPress Groups</li>
<li>Random</li>
</ul>
</li>
<li>Widget Area Designer 
Add responsive widget columns and edit colors, backgrounds, paddings, etc.</li>
<li>Widget Areas in Theme Hooks 
Intelligently infuse new widget areas into your theme without coding</li>
<li>Automatic Widgets Backup 
Easily restore any changed or deleted widgets</li>
<li>Widget Cleaner 
Save memory and remove clutter by disabling and removing unused widgets</li>
<li>Extended User Visibility 
Show or hide widget areas for User Roles, BuddyPress Groups, and more</li>
<li>Time & Weekday Schedule 
Display widget areas only in select time ranges on given days</li>
<li>Container Widget 
Turn widget areas into reusable blocks and show the same widgets in different places</li>
<li>Duplicate Widget Areas 
A real time-saver when adding new similar widget areas</li>
<li><a href="https://dev.institute/wordpress-sidebars/pricing/?utm_source=readme&utm_medium=referral&utm_content=more&utm_campaign=cas" rel="nofollow ugc">and so much more…</a></li>
</ul>
Upgrade at anytime instantly and securely from your website’s Admin Dashboard.
<h3>More Information</h3>
<ul>
<li><a href="https://dev.institute/docs/content-aware-sidebars/?utm_source=readme&utm_medium=referral&utm_content=info&utm_campaign=cas" rel="nofollow ugc">Documentation</a></li>
<li><a href="https://github.com/intoxstudio/content-aware-sidebars" rel="nofollow ugc">GitHub</a></li>
<li><a href="https://twitter.com/intoxstudio" rel="nofollow ugc">Twitter</a></li>
</ul>

Content Aware Sidebars – Fastest Widget Area Plugin

Display new sidebars on any post, page, category etc. Works with Classic Widgets, Block Widgets, and all themes!

Sidebar-Content from Shortcode vs Content Aware Sidebars – Fastest Widget Area Plugin