WordPress

Change your WordPress Salts:  https://api.wordpress.org/secret-key/1.1/salt/

(Copy the code you see, and replace it in your site’s /wp-config.php)

WordPress management tool, manage several sites from one location:  https://mainwp.com/

 

CSS

“Just add water” CSS animator:  https://daneden.github.io/animate.css/

 

Magento

How to perform Magento database maintenance: https://docs.nexcess.net/article/how-to-perform-magento-database-maintenance.html 

Google

Issues with API Keys?  Validate yours here:  http://yougapi.com/tools/google-api-key-checker.php

DIFF Tool

This is my fave because not only can you compare code side by side by you can quickly and accurately edit http://www.mergely.com/editor

HTML

Quick and easy online editor when you need one https://html-online.com/editor/

Icon Maker

Need a standard icon? Want to change color and size? This is the easy tool for you.  https://tablericons.com/

Magento Tutorials from MagePlaza

https://www.mageplaza.com/kb/magento-2-tutorial/

Cookie Database

Have a problematic cookie? Search it by name to determine what resource it is coming from https://cookiedatabase.org/

Graphic/Photo Editor

PhotoPea is browser based, no download, and is very similar to the basic Photoshop settings. Fun to use in a pinch!  https://www.photopea.com/