I usually play Nf6 and hope they play d4. Then it transposes into a more common indian or gruenfeld defence. Even if they play Nc3 first it can still transpose after g6 or e6.
Black response against the english open

What do you play against 1.d4 ? Sometimes you can use the same defensive set-up against both moves and simplify your repertoire.
For example, if you play the QGD (1.d4 d5 2.c4 e6), then it works against the English as well : 1.c4 e6 2.Nc3 d5
If you want to play with 1...e5, a standard set-up is the 4 Knight (Nc6, Nf6 and ...d5), which goes like this :
What is a good defense for black to use against the english open by white? Generally when i face someone using the english open some of my reponse moves are e5, Nf6, Nc6, and Bc5 (of course depending what is allowed after whites additional moves).