Majestic provides an array of different quality metrics for domains and allows you to explore the backlink profile for a website. Citation Flow and Trust Flow are great for determining the worth of a domain.
DomDetailer can be used for getting the Moz and Majestic stats for domains. Integrated directly into Domain Hunter Gatherer; this is the best option for getting domain stats quickly and at minimum cost.
Shared Count allows you to see the number of social shares for a domain. Get a view of a domains social history with information from Facebook, Twitter, LinkedIn, Pinterest and Google+.
Moz is a good way of supplementing quality information from Majestic and SharedCount. Domain Authority is clear and concise as a quality metric.
Ahrefs have their own proprietary quality Metric like Moz and Majestic but its strength lies more in its site explorer so it is better used for more in depth checking.
When building lots of websites you will need lots of content. WordAI has the best content rewriting hands down and will generate readable variations to your existing text in no time.
This page will be added to as more services come to mind. If you have any services or software you are interested in and would like to know if there are any deals available for them then get in touch and I will try to work with the developer to cut a deal for it.