I can give you one very specific answer in that my late father decades ago worked in IT for a collections agency and one way that biz works is they pay a fixed amount to buy some companies 120+ day accounts receivable file (the feds and every state highly regulates this and its highly variable and complicated, but this is the simplified version...) and this gave them a vast pile of records and legal ability to collect the debt. Now obviously they got most of their revenue by annoying the heck out of debtors right up to the legal limit. But they're leaving money on the table if they don't resell all the data they can legally sell. So sure, even 20+ years ago collections agencies were uploading records to various data aggregators in exchange for a check. Not just the original debt but followup activity and intel WRT the collections process. I would imagine that's only increased over the last couple decades. Most of these data transfers were two way streets, not simple data for money trade, and obviously they maximized profits by leaning the hardest on the people most likely to actually pay up, they did not waste time on debtors known to other collections agencies as hopeless deadbeats.

There is no such public list. Most of these companies are privately held, their methods are trade secrets, and there is no real form of legal recourse. Your best bet would be to buy a book like this: https://www.amazon.com/Hiding-Internet-Eliminating-Personal-... and follow the recommendations, but even that is only likely to be half-effective.

Much of the public information is mined from sources like credit headers, your court records, utility bills, property and tax assessment records, voter registration lists, motor vehicle registrations, etc.

Unfortunately, the legal and technological landscape is such that 'hiding' from these kinds of services is effectively impossible.

If I was a company, I would be writing scraping engines that scraped

* police 2 citizen (a platform many counties and municipalities use to report crime and accidents to the public)

* any public facing dataworks plus web application (or whatever various other municipalities/counties are running): the one for the county I live in lists the arrestee's employer

* district level and state level court dockets

* real estate records, which also link up to tax bills

* public voter records

Not surprisingly, only the information I've ever listed on my voter ID has ever showed up in Intelius/LexisNexis databases.

I can provide all the sources used for the company I used to work for, however that's irrelevant if you as you said wanted to learn how to fish.

Any and every company selling data and there are thousands is in fact a source you would need to deal with to be removed from the sites that sell it. If you think this answer isn't specific enough, you're not going to achieve anything by me spoonfeeding you info for one such company.

If you ever buy anything with a CC, use a "membership" card anywhere, or have anything delivered, or for that matter purchased online, then there's a greater chance than not this data was shared by the merchant, transaction provider and/or the credit card company themselves.

If you have an online profile, with any friends that aren't paranoid, and allow your friends to see any private information, then this can be collected/correlated by the various bot farms.

> There can't be nearly as many sources as there are sites who buy from them.

Sure there can. The sources include state, county, and local governments. There are a lot of those.