I’ve been browsing this website Center for Constitutional Rights and think others may be interested in it, too. Here is a brochure called
I just glanced over the brochure. It explains the rights of the FBI, NSA, etc. and the rights of citizens. Basically, as most of us have learned (the hard way), these federal agencies have a lot of leeway when it comes to surveillance, intimidation, and harassment. However, I think you’ll find the organization and its resources helpful.