What are your top databases & platforms for more narrow industry research?

Caerus Ventures, my lower middle market private equity firm, is actively searching for companies to acquire in the manufacturing and distribution space. Until now, we have seen extremely niche companies that operate in industries like horizontal drilling or production of industrial steel dairy containers. While we are liking these companies and believe that their margins are healthy, but we are having a hard time finding industry research, apart from broker-provided information which may be biased. Any tips on narrowing down our search criteria for industries? Do you have any favorite manufacturing industry research databases? Thank you, Searchfunder community!