Against 1-d4

if you like active play I will suggest you to play Benko gambit, KID, if you're positional player probably Queen's gambit declined.

You can still play 1.c6, even against d4! Because if they play 2.c4, then you play 2.d5, transposing into the slav. Then if they play 2.e4, then you can play the good ol' Caro khan!

@Susik_Gaboyan well, she's just 1000 so i think KID would be too complicated for her. Maybe queen's gambit accepted would sort it out.

If you are aggressive and play for checkmate often like me, flamingo system may be work for you. It is easy to apply and there is not much theory behind it. But it comes with downsides like neglecting queenside play and glass cannon like gameplay so you may only get one chance to attack properly so you should plan your attack very well and keep as much pressure on kingside as possibile.

edit: I confused the flamingo with pelican sorry about dat lol

Correct me if I am wrong, isn't pelican Sicilian? They are talking about d4 lines as black.

@MYMChessIan Ah damn I confused the names of openings lol.

it's true it shoulda be flamingo not pelican sorry for misinformation

Soltis wrote a book on playing black, which recommended playing Caro-Kann or Slav setups against any white opening. Good book but outdated now in many variations.