semi-slav?
What should I play against 1.d4?

KID for aggressive and sharp. Kind of like a Sicilian against 1.e4. I personally like Nimzo-Indian best as it is very dynamic and sharp. Black can get iniative with the get go, like KID.

Play this
I win 100% of my games with that opening
No, white gets a lot of activity and iniative IMO.

Play this
I win 100% of my games with that opening
This gains lots of advantage for white imho.

Modern chess has shown there are many excellent opening that can be played at all levels. Choose a main line that you enjoy and that you can grow with. Don't worry too much if the engine gives White a +.5 or whatever. As long as you understand the positions, you can score wins against anyone who isn't a professional. And you can even beat the pros occasionally if you really understand the lines.
One of the most common mistakes a class player can make is to blame the opening for his or her losses. They keep switching openings in the hopes that will give them better luck.
The remedy for losing isn't changing openings, it's improving the rest of the game!

Modern chess has shown there are many excellent opening that can be played at all levels. Choose a main line that you enjoy and that you can grow with. Don't worry too much if the engine gives White a +.5 or whatever. As long as you understand the positions, you can score wins against anyone who isn't a professional. And you can even beat the pros occasionally if you really understand the lines.
One of the most common mistakes a class player can make is to blame the opening for his or her losses. They keep switching openings in the hopes that will give them better luck.
The remedy for losing isn't changing openings, it's improving the rest of the game!
Oof. This is correct.
I am not sure what I should learn to play against d4. I have experimented with the Benko, Benoni, Grunfeld and the Kings Indian. I also used to play the QGD. Usually when I face d4 I either fail with the Benko, Benoni, or Grunfeld, or I lose slowly tiring to play Indian game stuff. I don't really like any of the positions I get against d4. What do you recommend I learn? Are there any Ideas that I may have not tried in those other openings?
Thanks,
Let me know if you have ideas