I have created an excel spreadsheet of 810 words and related add-ons organized by niches and use specifically for domain names (screenshot above).
For example, here are some positive adjectives you can describe most second words with to make a good domain:
On the other end, here are some good financial/money words you can combine with those words:
You can get lists for free but they’re not organized. NameStation.com’s premium subscription is organized but they have a lot of irrelevant keywords mixed in.
I’ve honed down my spreadsheet to what I think are the outer limits of general usage keywords, suffixes, or prefixes within their respective category and then stopped there.
I could expand the number of words to 1,500 but I don’t think that would be useful.
As of July 19, I’m figuring out how to sell this as a protected spreadsheet. If you’d like me to email you as soon as it becomes available, leave a comment below and be sure to include a real email in the email field (you don’t have to put it in the comment box).