Excellent question. There are quite a few free online public records databases, though none are as good as services that you can't afford to subscribe to unless you have grips of cash. That gets on my nerves, since there is not much point to publicly available information if it's not publicly available.
However, for money-folowers, off the top of my head:
(searchable federal contract and grant database, by agency, contractor, grantee, year, etc.)
(searchable database of campaign-related money and statistics, personal financial disclosures of House members, etc.)
http://www.newsmeat.com/media_political ... cManus.php
(searchable campaign contribution database that's easier to use if you're looking for an individual donor)
(annoying but comprehensive database of feder ostensibly greater-good non-profits that the IRS requires a Form 990 from.)
And...there are many others. It's worth remembering that all public record information is not necessarily accurate, it's just what the party that's required to make it public is averring to be accurate.
I will continue to add as it occurs to me. But for the moment, on a state and local level, online availability varies according to state and locality. Whatever's available will probably be somewhere on the Secretary of State's site or the County Clerk's site. (Various corporate dox, sometimes deeds or property transfer records, registered fictitious business names, and so forth.) There are also state archives (for example, surprisingly accessible Texas State Archives) and a large number of university and library sites that may have some online access to the personal papers of various public figures online (correspondence, etc).
FOIA records are all over the place, and it would be very nice if they were instead in one place.
I believe that The Sunshine Foundation and Crew recently launched a cooperative effort of this kind, and there are a few others, which I will make an effort to remember.
Wikileaks is an excellent research playground, imo.
I also recommend the Secrecy News blog at fas.org
And...I think the thousands of pages of mind control dox probably refers to the stuff that formed the basis for "The Search for the Manchurian Candidiate." I have seen what purported to be that in a free downloadable form, but cannot recall where. Someplace pretty easy to find via Googling "Mind Control" as I dimly recall.
Is there something in particular you're looking for, or is this just a general: "Okay, where do I go for primary source material" type question?
I do go to irs.gov and fec.gov for various forms that are not online elsewhere. But I try not to go .gov if I don't have to, because I like to live in a dreamworld where I'm not constantly acquiring horrible tracking cookies or spyware or whatever that I don't even understand everyplace I do online research, but rather ONLY on .gov sites.
Which is ridiculous of me, but there you have it