I think the best options are the Queen's pawn (d5), Dutch (f5) or Nimzo-Indian.
Best Opening against 1.D4


There are a finite number of good responses to 1.d4, but no one is better than the others.
The following are your options. There are other lines, but they are inferior. It is simply a numbered list and NOT rankings:
1) Queen's Gambit Accepted
2) Queen's Gambit Declined*
3) Slav
4) Semi-Slav
5) Nimzo-Indian* (Must also know Queen's Indian or QGD)
6) King's Indian
7) Grunfeld
8) Dutch
* - You must also know what to do against the Catalan if you play one of those with an asterisk.

black is completely fine in the queen’s gambit
also the Slav is just as good as the QGD, some say even better. Why are you saying it’s bad?

op doesnt want a g6 or b6 system
so... (assuming white plays d4 c4)
NID (if Nf3 then some QGD semi slav or bogo indian)
QGD
semi slav
regular slav
QGA
dutch
maybe more idk

I believe that all players should learn to play the Queen's Gambit Declined, at some point.
It's very principled and quite instructive.
Even if you decide that it's not for you, chances are you'll still learn something useful from the exposure to it.
These days, I prefer the Nimzo-Indian / Queen's Indian / Bogo Indian. But I consider the time I spent studying the QGD to have been quite helpful, as the ideas from the QGD sometimes overlap.

QGA as everyone learns QGD and don't know what to do if you take on c4.
No offense, that’s an outright lie. Not only is playing chess based on hoping your opponent doesn’t know how to play a very bad habit, but the second thing QG players learn is the QGA, and usually, black gets somewhat poor results.

no offense but that looks impossible to go through
especially without names given, or something
so... many.... brackets....

wow
also, PLEASE put the most deepest lines as top as possible
it would help
e.g. there Nf6 had more lines so it could be the "mainline"

What is the best approach against 1. D4 for Black (mainly for intermediate players;I am 1285 rated in rapid Chess at the time of posting)? I am tired of just using fianchetto openings and systems (King's Indian, Grunfeld, Queen's Indian, Modern etc) against the Queen's Pawn Opening.
Depends on what you play against e4. If you play the french you can try e6 with potentional dutch or nimzo-bogo transposition(not boring).
If you play the caro kann, you can try out the c6 move, with an intent to lash out d5 or some other tricky moves
and you can also use the anglo-slav(lion defence in another move order) if not sure how to respond(like if they make unusual moves)
If you play the sicilian dragon, the old benoni is for you
And, well. You can play D5. Thats how I like to think about d4. Just choose the defence like you did against e4.
What is the best approach against 1. D4 for Black (mainly for intermediate players;I am 1312 rated in rapid Chess)? I am tired of just using fianchetto openings and systems (King's Indian, Grunfeld, Queen's Indian, Modern etc) against the Queen's Pawn Opening.