Dumped all fallout 4 strings, you can find all console commands, ini settings, launch argument and other hardcoded strings here.

Updated note:
I managed to dump every default ini value from game, complete Fallou4.ini files include in update archive now. Also i discovered awesome techique of tweaking game ini:

1) You have to unpack default complete Fallou4.ini dump in Data folder.
2) You have to apply your initial tweaks (that you already had in documents folder) to this file, and can look at another over 2000 settings to tweak. I found a lot of useful stuff there such as camera controls, and screen space reflections tweaks.
3) Fallout4 will use Data\Fallou4.ini AS TOP PRIORITY OVERRIDE FOR ANY OTHER INI!
4.A) During the game you can alt tab and edit ini then return and type "refini" in console, or you can use network share to edit file remotely or use second display to avoid alt-tabing.
4.B)Also you can just use opened INI as template but use in game command setini "inisettings:inisection" value to see how it affects game in real time, but do not use refini or your settings will be lost.
5.B) To save any settings you set in console type saveini and all changes will be save in fallout4.ini

Warning: some settings will apply only if you restart game but most of them can be edited now easy during run-time.

P.S. - I suggest to enable mods by adding this list (taken from my dump, way more complete and official than one people use):
TEXTURES\, MESHES\, FACEGEN\, INTERFACE\ , MUSIC\, SOUND\, SCRIPTS\, MAXHEIGHTS\, VIS\, GRASS\, STRINGS\, MATERIALS\, LODSETTINGS\, MISC\, SHADERSFX\, PROGRAMS\
to sResourceDataDirsFinal inside DATA\FALLOU4.INI

Oudated note:
Its advised to look at file manually, but you can speed up process and find most of ini tweaks by using few regexp patterns:

1) search anything that starts with any lowercase letter, or specify lowercase b (boolean) or f (float), followed by any uppercase letter or number, than any number of letters or numbers

2) search anything that starts with any lowercase letter, or specify lowercase b (boolean) or f (float), followed by any uppercase letter or number, than any number of letters or numbers, followed by literal : , and then by any number of letters or number, followed by end of line

this will give you out strings like

fSomethinBlahBlah:Something

:Something part is ini section name
but some ini settings does not have ini section name specified so 1st pattern is more universal.

Console commands mostly stacked in single massive of lines, you can identify section with console command by looking at pattern that looks like:
onecommand
command
another command
long description of what this command does

Description of command is usually 2 lines bellow command it describes , so that pattern is like this:

command1
command2
command3
description of command 1

Since most of commands does not exist in INI file you will have to test their default values. The easiest way to do it, would be:

1) Create text file in Fallout 4 root folder, give it short and easy name you can remember and that will time less of your time to type, like getini.txt
2) Put all of your findings like fSomethinBlahBlah:Something and bSomethinBlahBlah:Something in there, add " before and after such ini strings, put getini in begining of each line, you can automate it with notapad++ search and replace with regexp. so the pattern would look like this
getini "fSomethinBlahBlah:Something"
getini "bSomethinBlahBlah:Something"
...
getini "fSomethinMoreBlahBlah:Something"
getini "bSomethinMoreBlahBlah:Something"
3) Run Fallout 4, open console with ~ button, and type:
bat getini

Now you will see default values of every hidden ini sitting you found in my sting dump. If you will see that no cvar was found or nothing was found that you made a typo most likely and should try to manually enter same line in console with correction to check if its your fault, otherwise you probably found remains of code from previous bethesda games, that was disabled in Fallout 4.

You have to write them all down old fashioned way on paper, o make a screenshots and use text  recognision programs to easily convert screenshots to text without typing a lot of vars. Sorry, i have not yet found any usefull command that would allow to dumb entire console buffer into text file. If you know one, let me know.

About 80-90% ini settings i found actually have values assigned and recognised by game, but changing them may not give you any visible effect anyway, so dont have high hopes about this.

To change setting right in game you should use 

setini "bSomethinMoreBlahBlah:Something" float\boolean (for example 1.0 or 1\0, you can have negative float values as well, letter in begining of each ini setting should give you idea if value should be float of boolean).

Some settings may need restart of game and to be entered in Fallout4.ini.

If you want game settings to be reseted to what present in ini files, type:

refini

But settings that was not present in ini would remain the same as you set them until you restart game, that why you need to write or screenshot (or dump if you know how to do it in this game) default values.

example.txt file included to give you better idea of how it works, put it in fallout 4 folder and type bat example in game

Actually i wanted do make complete list of everything myself using this method, but had not enought time yet, so im sharing this dump and easy way to search for working hidden ini settings and tweaks.

Post your finding and what works and whats not and what exactly it does in comments please!

Update:
Thaks to Cagelin for filtering out almost complete list of ini settings and making ini and bat template. They are included now in update file, please re-download if yoy got file prior 19 nov 2015.
Only cvars that had not ini section names references was skipped, in not sure where to put them, maybe in global or before any section?

Now you have to type this in console:
bat Fallout4_over2000ini_bat

and game will show you default values of over 2000 settings.

Since i still dont know if there is a way to dump console on disk you will have to write down on paper screenshot each chunk of settings and then manually add them to template ini. Also im not sure yet if fallout 4 console can handle such a big bat file and keep entire list in buffer, so its possible that list would be needed to split into chunks.
To ease your pain you can try this mod for bigger console.

Also i found out alternate console command to setting cvars, it would would be

setgs instead of ini and i think you dont need to add ini section name and ""
so
setini "bSomethinMoreBlahBlah:Something" 1
would turn into
setgs bSomethinMoreBlahBlah 1

but im not yet 100% sure about this, try various combinations and see if that work and then tell me in comments what did, and what did not work.

Same apply to GetIni, instead you can use GetGS.