“It’s good to be in something from the ground floor. I came too late for that, I know. But lately, I’m getting the feeling that I came in at the end.” —Tony Soprano

You’re wrong about that one, Tony. It may be that no TV show does anything entirely new — change always builds on change. But “The Sopranos” was as clear a marker of the beginning of an era (even if I hate the term “Golden Age”) as anything in TV.

Before “The Sopranos,” yes, TV dramas could take risks (“Twin Peaks”) and tell stories about difficult people (“NYPD Blue”). But after the ducks landed in Tony’s backyard pool in January 1999, an immense flock followed. TV series, we saw, could rely on audiences to pay close attention to a long-running story. They could have high visual and narrative ambitions. They could resist quick answers (or any answers, in the case of the Russian from “Pine Barrens”) and tidy moral conclusions.

If “The Sopranos,” which debuted 20 years ago this week, built the ground floor, this list looks at what TV erected on top of it. These are the 20 best drama series to emerge since “The Sopranos,” arranged in chronological order.

For the sake of focus and sanity, Mike Hale, Margaret Lyons and I limited our debates to American series TV drama. What is American? (Shows made specifically for the United States TV market rather than acquired.) What is a series? (Shows that were meant to continue more than one season.) What is TV? (What isn’t, these days? Anything broadcast, cable or streaming was fair game.)

Oh, yeah: What is “best”? It’s not “most influential” (sometimes great art is inimitable) or “most widely praised” (a cop-out). Here, it’s the subjective, rough consensus of three humans, each with different tastes and priorities, after argument and bargaining. It ain’t science. The final judgment, while hopefully well-informed, is no more inherently right than yours.

The trickiest question, though, was, What is a drama? Episode length isn’t an absolute guide, and awards nominations are no help. (“Orange Is the New Black,” say, has been Emmy nominated as both comedy and drama.)

I’d like to say we came up with some bulletproof formula — length plus tears divided by jokes — but truth is, we went by feel. “Transparent,” by our lights, is clearly a drama, awards submissions notwithstanding; “30 Rock” is plainly not. The nebulous in-between zone is where some of the best TV is being made now, and that’s where some of our later picks come from (like “Atlanta,” which can be TV’s best drama or its best comedy any given week).

If our resulting list stretches the definition of drama, good: “The Sopranos” certainly did. (It was the funniest show on TV most weeks it was on.) You’d swap out some shows here and there. (So would we, individually, and we wrote about some of our near-misses too.) But step back, and I think this list broadly tells the story of what American TV drama has become over two decades.

Looking at this period historically, or geologically, I see three somewhat overlapping sub-eras. Concurrent with “The Sopranos,” a set of dramas took TV staples (the cop show, the western, the sci-fi saga), roughed them up and problematized them. Next, starting around “Mad Men” (from “Sopranos” alum Matthew Weiner), drama ventured into more varied subject matter (and a greater variety of outlets).

Finally — the period we’re still in now — came the Great Diversification, not just of characters (Tony’s early followers were a lot of middle-aged white guys with agita) but formats, styles, voices and tones.

What comes next? We were conscious (and maybe a little surprised) that only one streaming-TV series made this list. I’ve theorized before that just like in the early days of TV, comedy is more easily adaptable to new platforms, whereas drama is still figuring out how to mesh episodic TV with the endlessness of the binge. Very likely the next version of this list (which you’ll read in 10 or 20 years on your corneal implants) will reflect how the next wave of dramas evolved to master that format, and maybe others.

“The Sopranos,” we all remember, ended with a cut to black. The genre that followed, though, takes its cue from the lyrics of Tony’s final jukebox selection, “Don’t Stop Believin’”: It goes on and on and on and on.