SwiftNinjaPro

This plugin blocks non-admin users from using inspect element, while still allowing access those with manage_options permission. 
The plugin also blocks some of the common keys(f12, ect.) and optionally can block right-clicks for non-admin users. 
Admins are unaffected by the plugin entirely. This plugin is also able to block users who open developer tools on another site, before visiting your site.
Version 3.0 update
This plugin is now fast and accurate, and should work on most browsers. 
This plugin can detect the browser console based on lag increased by opening the console. This detection is tough for a browser to prevent or get around. 
The detection runs fast, and has some resistance to lag spikes.
Lag detection does mean your site needs to have ok performance, but when testing it, I could play 10 of 10 youtube videos all at once without a false positive. 
During my tests, detection was still within the second I open dev tools, and successful if I go to the page with it already open. 
I tested this in chrome, firefox, and chromium. 
I also tested this on my somewhat slow website with tons of wordpress plugins installed (and the 10 videos at once test) without false positives.

Developer Tools Blocker

This plugin blocks non-admin users from using inspect element, while still allowing access those with manage_options permission.

Gregory

The Plugin Inspector plugin is an easy way to check plugins installed on your WordPress and make sure that plugins do not use deprecated WordPress functions and some unsafe functions like eval, base64_decode, system, exec, etc. Some of those functions may be used to load malicious code (malware) from the external source directly to the site or WordPress database.
Features
<ul>
<li>Scans plugins for deprecated WordPress functions</li>
<li>Scans plugins for unsafe functions like eval, base64_decode, system, exec, etc.</li>
<li>Checks plugins to find vulnerabilities listed in WPScan Vulnerability Database</li>
<li>Beautiful source code viewer with highlighting</li>
</ul>
Plugin Inspector allows you to view all the deprecated functions complete with path, line number, deprecation function name, and the new recommended function to use. The checks are run through a simple admin page and all results are displayed at once. This is very handy for plugin developers or anybody who want to know more about installed plugins.
All code that uses the deprecated functions should be converted to use its replacement if one exists. Because deprecated functions are no longer supported may be removed from future versions of WordPress.
To check the theme files, please, use Theme Check plugin.
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Plugin Inspector

Every plugin developer should be using this.
Thankyou Gioni.



Beautiful

Very useful for plugin developers to run a quick check of their code throughout development.



Great plugin

Works as advertised. Very scary to see so many plugins have so many security issues. As long as WordPress allows unsafe themes and plugins to get activated, it will never be safe, no matter how much they secure the core.



Very Cool !

Thank you very much for developing this plugin and keeping it up-to date.
Thankful to your efforts and time.



Nice Plugin

Checks plugins for deprecated WordPress functions, known security vulnerabilities and some unsafe PHP functions

Developer Tools Blocker vs Plugin Inspector