is your email on a blacklist?

https://mxtoolbox.com/blacklists.aspx

completely royalty free, free images for commercial or other use

https://unsplash.com/

HTML meta tags checker for SEO

https://smallseotools.com/meta-tags-analyzer/

open graph facebook tags checker

https://developers.facebook.com/tools/debug/

useful analysis of SEO on web site

https://app.neilpatel.com/

testing your computer and browser for 3d speed or power

https://www.wirple.com/bmark/

Keyword search volumes for a particular keyword

keyword volumes
https://www.wordtracker.com/search?query=metal%20home

comparing popularity of searches
https://trends.google.com/trends/explore?geo=US&q=barndominium,metal%20home