When it comes to smaller public companies, the exchanges list their companies by Market Cap. You can explore them there. ESOPs are easier to discover via internet search. This is a good resource for ESOP’s : https://www.nceo.org/employee-ownership-data/esop-company-lists.
For VC backed and PE backed companies, it’s best to do some research on the internet to find which firms invest in companies within the industries you are interested in.
A great resource for finding companies of interest is crunchbase.com or pitchbook.com.