Note: Some of the database interfaces have changed since this video was recorded. I am working to update videos, but in the meantime I would advise that all of the same data should be available and if you're having trouble navigating, please don't hesitate to email me. I am always happy to help.
Some resources will organize industry information by an industry classification number. I highly recommend noting this number (sometimes multiple numbers) when you come across it in your research. It might help you search or browse other resources.
There are two main classification systems:
The North American Industrial Classification System (NAICS) is the newer system. It was most recently updated in 2017. This means it has more cutting edge industries included, though admittedly there are always emerging industries that classification systems haven't caught up to yet.
The Standard Industry Classification (SIC) was the system NAICS replaced in 1997, but some resources are still organizing their information by SIC code, so it can still be a useful number to know. (The Securities and Exchange Commission, for instance, still includes SIC for the standard filings.)
In some instances a company designates its own primary NAICS and/or SIC code, and can also have other associated codes, and in other instances a government agency etc. might assign a primary code based on their assessment of what the company does. So you might find a few different primary codes depending on where you're searching and it can be worth considering which ones you want to use in determining industry competitors etc.
The Kauffman foundation supports entrepreneurs through education, the creation of learning communities and providing relevant research and data related to entrepreneurship in the United States. Of particular interest might be their 1 Million Cups meetings (in Columbus) or their online learning resources on Entrepreneurship.org.
GEM produces multiple reports and data that may be of interest, particularly their Economy Profiles, which explore entrepreneurial behavior and infrastructure in a country, and their datasets which let your explore comparisons between countries re: things like financing available for entrepreneurs, taxes, government programs and more.