Devtard

This plugin overrides default date and time of edited posts with dynamically calculated custom values. This is useful especially when scheduling posts; the plugin can, for example, automatically generate new post dates by incrementing the current most future post date by a specified number of days.
Calculated custom date and time will automatically replace default values after clicking the “Edit” link next to “Publish immediately” in the post editor’s Publish module.
<h4>Features</h4>
<ul>
<li>Date/time values usable as a reference: current date/time, oldest or most future post date/time; specific time of day</li>
<li>Date/time of reference can be increased or decreased by a specific number of days/minutes</li>
<li>Configurable post types and statuses of analyzed and affected posts</li>
</ul>
See <a href="https://wordpress.org/plugins/automatic-post-date-filler/screenshots/" rel="ugc">Screenshots</a> for more information.

Automatic Post Date Filler

Automatically sets custom date and time when editing posts.

Mark Costlow

Future Dater is a simple plugin to provide a shortcode to include certain types of future (or past) dates in your posts or pages. The type of dates supported are “beginning of next quarter”, “last day of this quarter”, “first day of next month”, etc.
Features
There are 4 arguments to the [futuredate] shortcode:
<ul>
<li>
unit – Required. Which part of the current date you want to modify. Valid values: “month” and “quarter”.
</li>
<li>
relunit – Optional. Whether you want reference the first day or last day of the unit, or the same day as the current date. Valid values: “first”, “last”, or none.
</li>
<li>
count – Required. How much to modify the current date, in units specified by the unit argument. Most commonly 1 (for next month or next quarter) or 0 (for the current month or quarter). Also accepts negative values.
</li>
<li>
format – Optional. PHP date-formatting string to specify how the date should be printed. Most common value: `Y-m-d’.
</li>
</ul>
Examples
<ul>
<li>
The end of this month: [futuredate unit=month relunit=last count=0 format=”Y-m-d H:i:s”]
</li>
<li>
The end of this quarter: [futuredate unit=quarter relunit=last count=0 format=”Y-m-d”]
</li>
<li>
The first day of next quarter: [futuredate unit=quarter relunit=first count=1 format=”Y-m-d”]
</li>
<li>
The end of the quarter, 5 quarters from now: [futuredate unit=quarter relunit=last count=5 format=”Y-m-d”]
</li>
<li>
The end of previous quarter: [futuredate unit=quarter relunit=last count=-1 format=”Y-m-d”]
</li>
<li>
First day of next month: [futuredate unit=month relunit=first count=1 format=”Y-m-d”]
</li>
<li>
Two months from now: [futuredate unit=month count=2 format=”Y-m-d”]
</li>
</ul>

Future Dater

Adds a shortcode to include a specific kind of future date (such as "first day of the next quarter" or "Last day of next month").

Automatic Post Date Filler vs Future Dater