What is your opening combo for black?

What are your preferred defenses against 1.e4 and 1.d4? I am trying to find out the most popular combo out there.

E4 has many

Caro kann, sicilan, Scandinavian,french, modern and the e5 defenses

D4has

D5(leads to queen gambit if white plays b3), and more are there

Sicilian against e4

Nimzo-Indian, Bogo-Indian, King's Indian, or QGD against d4 - depending on what White does.

Opening combos caro+slav, Najdorf+kings indian/grunfeld, Pirc+kings indian where you guys at?

Petroff and Dutch

D4-e3-C---

Kinda complicated so I'll show the lines.

Caro-Kann / Slav

Against 1.e4 The Center Counter Defense either the Mieses Var 3...Qa5 or the Czeb var (fiancheto version of 3...Qd6.

Against 1.d4 The tried and true QGD "Orthodox" variation. It can't be moved ordered... and Below Master level chess, past move 6 of it's it's "tried and true" theory White majority of the times flounders (No longer popular below the Master level ... Bonus !)

Although... lately I have been playing the QGA against 1.d4. Early on it appears more tactical than the QGD, more to go wrong... but like the Center Counter Defense, it gives Black a hard return volley right from the start... kinda my liking

Sicilian Najdorf against 1. e4.

King's Indian Defense against 1. d4.

Slav and Classical Sicilian. 
Popularity is something to be avoided if possible, though there's always a tradeoff in doing so. But I find these 2 defenses are rich enough to allow for new ideas in most scenarios.

I use Caro against e4 then Modern Transposing to Pirc or KID against d4 or anything else. Vs D4 i typically use 1. . .g6 instead of 1. . . Nf6 to avoid trompowsky

transposition is fun

Or in some cases not transposing to anything and being stuck in a Modern.

1.d4 g6 2.e4 Bg7 3.Be3 d6 4.Nd2 Nf6 5.c3 and you are in a c3-modern.

I'm playing the Benoni or Grunfeld with Black