Even with former Mayor Bill de Blasio now out of the race, there’s a crowded left lane to represent New York’s 10th Congressional District, the open seat in Lower Manhattan and brownstone Brooklyn.

And because the lane is not clearly defined, several candidates are claiming the progressive mantle.

“There is only one progressive candidate in this race with a track record of actually delivering progressive results in the United States Congress,” said Rep. Mondaire Jones, who moved into the district from the Hudson Valley, where he currently serves.

“People are really looking for a fighter, someone who understands what it means to live in a community that has been historically underrepresented,” said City Council member Carlina Rivera.

And Assemblywoman Jo Anne Simon touted her “record of being consistently progressive for many years. Nobody was taking on the Brooklyn machine in 2004. I was.”

Jones, far and away the fundraiser leader of the primary, is endorsed by the New York Progressive Action Network and the Retail Wholesale and Department Store Union.

Rivera is backed by the health care union 1199 SEIU and Brooklyn Rep. Nydia Velázquez.

Simon is the choice of several independent progressive political clubs.

The trio, along with and de Blasio, had sought the support of the left-leaning Working Families Party, which ultimately picked Manhattan Assemblywoman Yuh-Line Niou.

Niou described working “though a racial justice lens, disability lens, social-economic justice lens, environmental justice lens.”

Trailblazing former Rep. Liz Holtzman is another NY-10 candidate who identifies as progressive.

But a recent poll by the Working Families Party found Niou and Rivera tied as leaders in the field.

“Very important to me is to make sure that we are calling out what’s always needed to be said,” Niou said. “I think it’s important to always lead with authenticity.”

Rivera said, “it’s really about delivering also on the things we are fighting for, and really not letting a few voices be the enemy of the good.”

The race is packed with a dozen Democrats running and, with a month to go until the Aug. 23 primary, it’s gotten acrimonious.

“I’ve got the resources, the grassroots resources, to actually defeat a self-funding millionaire in this race who just came out as anti-abortion or at least supporting restrictions on abortion,” Jones said.

Dan Goldman, who was the House Democrats’ lead counsel for then-President Donald Trump’s first impeachment, said he misspoke on his position on abortion in an interview with Hamodia, a Jewish daily newspaper, and unequivocally supports a woman’s right to choose.

Niou, Rivera and Simon were among the others who called him out.

He is a threat to all their prospects: his war chest is the primary’s second largest.