People over complicate it. The answer is anything androgenic.
If you run test you'll look good and thicker. But toss in any androgen and areas like the shoulders, traps and quads all blow up. Doesn't matter which androgen it is. Just run whatever you respond best to, whatever's cheapest, etc. I'm starting to think that steroids don't really vary too tremendously when you look at how androgenic or how anabolic they are. Run a base of whatever you like and toss in something else. That's all it takes.
But to cut to the chase, good old tren ace always made my shoulders pop. I don't like it nearly as much as I used to when I was younger, but tren ace makes some quick visual changes in the mirror.