12 Best Practices for Contact Form Page Design (with Examples)
http://www.wpbeginner.com/showcase/best-practices-of-contact-form-page-designs-in-wordpress/

SEO

Free SEO Tools and Software

https://www.web-savvy-marketing.com/2016/04/free-seo-tools/

Beaver Builder

https://www.youtube.com/channel/UCjDuxPEhNQ2qn_qAdjRG4YQ

http://kb.wpbeaverbuilder.com/article/394-tutorial-create-a-header-layout-themer

For Developers

https://gist.github.com/malarkey/4031110

https://premium.wpmudev.org/blog/embedding-wordpress-oembed/

Ecommerce

https://www.websitemagazine.com/blog/don’t-neglect-these-10-e-commerce-design-decisions