WP Fix It - WordPress Experts

This is the easiest and fastest way to see if you have a conflict on your site. Disable all active plugins with a single click. You can also turn them all back on with a single click without losing any settings or functionality. You can also enable WP_DEBUG directly from your admin area with no need for FTP or server access. WordPress WP_DEBUG is a built-in debugging tool that when enabled, will display any PHP errors on the front end of your site.
The best part is this is only for the admin user. That means all other users will not see any errors or loss of functions with a plugin being off. So fast and easy to know instantly if there is a plugin conflict on your site causing an issue.
There is an option where you can enter the URL of the place where you are seeing an issue and this will preview on the options page so as you go through and deactivate plugins the preview will update and you can find which plugin is the culprit.
<h3>SUPER HERO FEATURE</h3>
In the event that there is a fatal error on your website and you get a website visitor, they will not see the error message but instead they will see a pretty page instead of the default WordPress error page.
<h3>HELPFUL INFO INCLUDED</h3>
This plugin also displays important WordPress information and the details of the hosting environment.
<ul>
<li>
Active WordPress version
</li>
<li>
Active WordPress Theme
</li>
<li>
Installed Plugin Amount
</li>
<li>
Available WordPress Updates
</li>
<li>
Server PHP Version
</li>
<li>
Server Software
</li>
<li>
Server Operating System
</li>
<li>
Server IP Address
</li>
</ul>
<h3>BEST REASONS TO USE THIS</h3>
<ul>
<li>
All changes are admin only so all other users are not affected
</li>
<li>
Quickly know if the error on your site is caused by an active plugin or theme
</li>
<li>
No need for FTP access to turn off all plugins. One click off and on
</li>
<li>
Turn on WP_DEBUG without needing FTP or server access
</li>
<li>
Find and isolate PHP errors directly from your admin area
</li>
<li>
Quickly view WordPress version used and hosting environment info
</li>
</ul>

Conflict Finder

This is the easiest and fastest way to see if you have a conflict on your site. All changes for admin view only.

Josh | wpCure

Dealing with Pluggable Functions can be tricky:
<ul>
<li>Which functions have been overridden by which module?</li>
<li>Each function can effectively only be overridden by a single module, leading to potential conflicts</li>
</ul>
This plugin attempts to shed light on the Pluggable Functions conditionally declared by WordPress Core. In case a function has been overridden (reassigned) by another module, such as a plugin or theme, the PHP file containing the effective declaration is shown.

Pluggable Functions Explorer

Check which Pluggable Functions have been overriden (reassigned), and in which PHP file

Conflict Finder vs Pluggable Functions Explorer