Great tool for checking DNS settings: https://toolbox.googleapps.com/apps/dig/#MX/
This is an awesome free yelp widget to display reviews on your website. Sad its no longer being updated but still seems to work as of today: http://chrisawren.com/widgets/yelp/
PDT Tutorial: http://www.paysketch.com/setup-paypal-pdt/
IPN Tutorial: http://www.paysketch.com/configure-and-setup-paypal-ipn/
Cool Line Art Creator Website: http://www.snapstouch.com/Sketch.aspx
Make PHP harder to read and steal: http://phpencoder.atwebpages.com/index.php
Very easy resources for converting the optimizing images for the web.
JPG Optimizer: http://optimizilla.com/
PNG to JPG: http://pngjpg.com/
Birme: https://birme.net/
This is a great free stock photo library: https://www.pexels.com/
Found this great article on getting free SSL Certs on your vertualmin servers: https://techjourney.net/how-to-use-lets-encrypt-ssl-certificate-automatically-in-virtualmin-webmin/
Here are the steps:
Configure and Setup Let’s Encrypt in Webmin / Virtualmin
Request and Install Let’s Encrypt SSL Certificate for Virtual Servers / Domains
Here is the link, lots of images what are very high quality: http://www.mb3d.co.uk/mb3d/Wood_Exterior_and_Planks_Seamless_and_Tileable_High_Res_Textures.html
Found this site as well: http://www.texturemate.com/content/free-texture-seamless-metal-2010092601