shawfactor

This plugin allows the following you to configure the backend new user screen to incorporate the following features
<ul>
<li>Optional use of email addresses only instead of username and email.</li>
<li>Optionally hide the new user url field</li>
<li>Optionally allow you to specify whether an email should be sent to each new user or not</li>
</ul>
These changes make adding new users to WordPress a lot faster.
One word of caution is that IF YOU USE EMAL ADDRESSES ONLly the plugin replaces the username with the email address of the user when a user is saved in the database. meaning your users will no longer have a separate username.
Check out <a href="http://lhero.org/plugins/lh-email-registration/" rel="nofollow ugc">our documentation</a> for more information.
All tickets for the project are being tracked on <a href="https://github.com/shawfactor/lh-email-registration" rel="nofollow ugc">GitHub</a>.

LH Email Registration

Streamlines user registration in the back end by allowing administrators to remove redundant fields and replaces usernames with email addresses

meloniq

Enables searching post meta fields on admin pages.

WP-Admin Search Post Meta

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LH Email Registration vs WP-Admin Search Post Meta