good black openings against d4


Against 1. d4, the more popular first moves are 1...d5 or 1...Nf6. As for which opening to choose against 1. d4 (not just first move), it really depends on many factors such as your playstyle, what middlegames you are comfortable with and how willing you are to study deep theoretical mainlines (if you aren't too willing, then you choose an opening which is more idea based and less precise study such as the King's Indian Defense).
Here is a video I made which might help you choose openings for white or black and links to opening resources, including a fun chess personality quiz which recommends what openings you might be good with for each side.