John P. Bloch

Create child themes from any non-child theme with the click of a button.
This plugin is multisite compatible; if used on a multisite network, controls for creating child themes will be in the network admin instead of the regular site admin. Pick the parent theme from the dropdown and name name your new child theme. You can also change the author name and select files you want to copy from the parent to the new theme.
Click the button and you’re all set!

Child Themify

Create child themes with the click of a button.

WenZe

Category Parent Children Selector is a WordPress plugin that helps you in selecting parent-children categories.
Features include:
<ul>
<li>Button to select all categories. </li>
<li>Button to select all categories including children categories. </li>
<li>Button to select first level of children categories only. </li>
<li>Button to select parent and all its children categories under its sub categetory. </li>
<li>Auto select parent categories when a sub category is selected.</li>
</ul>

Category Parent Children Selector

Helps you in selecting parent-children categories.

Child Themify vs Category Parent Children Selector