which opening to play against d4?

Simplest and best is 1 d4 d5.

Many relevant suggestions and resources relating to openings here...

https://www.chess.com/blog/RussBell

Play b5. Most of the time they're not expecting it so you won't need to learn any theory and then you can just play Bb7 and figure it out from there.

Old Benoni is pretty intuitive to learn and really annoying to play 1.d4 against. If you want to dedicate any study to a specific black opening vs 1.d4. This would be my suggestion. Your time will be well rewarded.

i think maybe King's Indian or Queen's Indian is best. they are aggressive ways to play as not only equalize with black but play for advantage.

Nimzo I don't like it seems very drawish, same as QGD (Queen Gambit Declined).

Don't get hung up on which exact opening you're playing. At your level (and up to a very high rating) it's fine to play the opening by the opening principles. In short with black you'll want to:

1. Get control over the center. Usually you do this by putting a pawn in the center, so 1. d4, d5 is a good start. Your goal is to prevent white from getting and keeping his pawns at e4 and d4. 

2. Develop all of your pieces to reasonably active squares. They should help you with the fight for the center. With black you usually can't be as active as white, but that doesn't mean you should only move on your own first 3 ranks. Make sure to be quick: every piece should move only once and you shouldn't lose time on pawn moves.

3. Get your king safe by castling.

If you follow these principles, you'll play the opening well and better than most of your opponents. No need to learn anything else.

Simplest is 1.d5. Tho I usually recommend englund, but its 2 traps dosent work on 3 digits. My 400 self plays 1.e6 tho.

they say it's the "best" because they want to sell their stuff lol

Old benoni is inferior to a normal benoni, yeah. But the game is still very complicated, and the advantage isn't quite clear until deep in the game.