helpgeek

By default, the built-in Recent Posts widget in WordPress only allows you to 
display up to 15 recent posts max, even if you specify a larger number. This 
is hard-coded into the WordPress core so any modifications you make would have 
to be redone upon every WordPress update.
No longer!
The Recent Posts Widget Unlimited functions exactly as the built-in WordPress 
widget but without the 15-post restriction. You can now specify an unlimited 
number of recent posts to display without resorting to modifying the WordPress 
core.

darrinb

Build a better post list.
The Advanced Posts Widget is an enhanced version of the default WordPress Recent Posts widget. It allows for greater customization and stying of your recent content lists.
Make your post lists stand out with this highly customizable recent post widget!
Features
<ul>
<li>Build multiple lists!</li>
<li>Select which post types to display. (You can choose either all types, or a specific type.)</li>
<li>Set the number of posts to show.</li>
<li>Choose how to order your posts: publish date, alphabetically, random, etc.</li>
<li>Set the order for displaying the posts.</li>
<li>Filter by category, tag, or custom taxonomy.</li>
<li>Supports post thumbnails.</li>
<li>Set and preview custom thumbnail sizes, or choose from your site’s registered image sizes.</li>
<li>Show an excerpt of the post.</li>
<li>Set and preview the length of the excerpt.</li>
<li>Select the list format to match your site’s markup. Choose from: <code>ol</code>, <code>ul</code>, or <code>div</code>.</li>
<li>Select the listing format. Choose between <code>html5</code> or <code>xhtml</code>.</li>
<li>Show post date.</li>
<li>Set and preview multiple date formats.</li>
<li>Choose the default (basic) CSS styling or roll your own.</li>
</ul>
Developer Features
This widget was built not only with end-users in mind, but also plugin developers. Almost every aspect of this widget is extensible through filters and action hooks. You can even add your own form fields to the widget form!
<ul>
<li>Need to remove a field from the widget form? Not a problem! Every field is passed through its own filter for easy customization.</li>
<li>Need to modify the output of the widget? Easy! The output is passed through numerous filters, allowing you to customize the post list to meet your project’s requirements.</li>
<li>For a full list of action hooks and filters, please see the plugin documentation: http://darrinb.com/plugins/advanced-posts-widget</li>
</ul>
For sample functions check out this small testing plugin: https://github.com/dboutote/Advanced-Posts-Widget-Testing

Advanced Posts Widget

I tested quite a few different Recent Posts Widgets and they all had bugs or outdated code or lack of flexibility or simple settings for their images and whatnot. This plugin does all the things you need:
* Set your thumbnail size from a list of registered image sizes
* Choose your category
* Choose your post type
* Even works with the Organize Series plugin well
* Order by recency, title, or even random (my favorite)
Combine this with the Display Widgets plugin and you have a powerful and flexible and intuitive sidebar that works great with your theme. 
Well done!



Exactly what my blog needed

A powerful and flexible recent posts widget for WordPress for displaying customized content lists.  Supports all custom post types and taxonomies!

Recent Posts Widget Unlimited vs Advanced Posts Widget