[21] DC/Vertigo published Romberger's work on the "Renegade" storyline in Jamie Delano's often reprinted miniseries 2020 Visions;[22] The Bronx Kill, a graphic novel with writer Peter Milligan;[23] and in 2011, the terrorism fable "Aaron and Ahmed," a collaboration with MacArthur Prize fellow Jay Cantor and colorist José Villarrubia.

[27] In 2021, Romberger expanded Post York to a graphic novel for Berger Books/Dark Horse;[28] it includes an afterward about the real effects of global warming on Manhattan, that he based on research done at his request by the sustainability thinktank Unbuilt Labs.

[29] In 2019 Romberger returned to Uncivilized Books with his semi-fictional comic about Jack Kirby, "The Oven," and a supporting essay in the first issue of what he says will be an ongoing, sporadic anthology title, For Real.

[30] Romberger in 2022 teamed with artist Josh Bayer for an etched 7" vinyl single and comic book for the Chicago punk band Naked Raygun's song "Broken Things," funded by a Kickstarter campaign.

The pair traveled to France with the filmmakers; additionally Romberger's fine art drawings are featured throughout the movie and he and Van Cook also drew narrative recreation sequences specifically for the production.