Forge12 Interactive GmbH

This plugin will track the load time of each plugin, javascript and css file 
to help you optimizing the performance of your WordPress site. It will help you 
to figure out which plugin / resource causing the slowness of your page.
Track time for:
<ol>
<li>Core</li>
<li>Theme </li>
<li>Plugins</li>
<li>Resources (JavaScript, CSS)</li>
<li>External files</li>
</ol>

F12-Profiler

Excellent! After P3 doesn’t work with PHP7+ anymore, F12 seems finally the one stepping in to fill that gap.

Update [18-Jun-19]. After some small contributions of mine to the dev efforts, the plugin developer has decided to add me to the team, long after this review was written.

Finally an alternative to P3

Trace the execution time of plugins, themes and core files to find the bottlenecks of your system.

tombenner

MySQL Profiler displays debugging information about SQL queries to admin WordPress users. For each query, the profiler displays the time, syntax-highlighted SQL, and a trace of the functions (as well as the file and line number that the functions were called from) that were called.
The list can be sorted by any of its columns, so you can, for example:
<ul>
<li>Order the list by ID to see the chronological order of the queries</li>
<li>Order the list by time to see the slowest queries</li>
<li>Order the list by query to group the queries by type (SELECT, UPDATE, etc)</li>
<li>Order the list by trace to group the queries by similar origins</li>
</ul>
The list can also filtered by typing in the search box, so you can, for example:
<ul>
<li>View all queries that use the wp_posts table</li>
<li>View all queries that are related to the use of a function in taxonomy.php</li>
<li>View all queries that are related to the use of a specific function or class</li>
<li>View all queries that call a specific MySQL function</li>
</ul>
To turn off syntax highlighting, put the following in wp-config.php:
<pre><code>define('MP_HIGHLIGHT_SYNTAX', false);
</code></pre>
To omit the file and line number from the function trace and display the functions as a comma-separated list (to save vertical space), define the following in wp-config.php:
<pre><code>define('MP_DISPLAY_FILES', false);
</code></pre>
This plugin was loosely based on <a href="http://bueltge.de/" rel="nofollow ugc">Frank Bueltge</a>‘s <a href="https://wordpress.org/extend/plugins/debug-queries/" rel="ugc">Debug Queries</a> plugin, so a hearty thanks to him for the development of that.
If you’d like to grab development releases, see what new features are being added, or browse the source code please visit/follow the <a href="http://github.com/tombenner/mysql-profiler" rel="nofollow ugc">GitHub repo</a>.

MySQL Profiler

Displays a list of each page's SQL queries and the functions calling them that can be searched and sorted by time, type, etc.

F12-Profiler vs MySQL Profiler