In Vigilante's car on the dashboard is a figure of Ultra Bunny, a fictional character James Gunn created for The Suicide Squad (2021). Rick Flag wore a T-shirt with Ultra Bunny on it for most of the movie, including when Peacemaker killed him. Vigilante's Ultra Bunny figure can be seen holding an English version of the sign shown on Flag's shirt, which reads "Obstacles are opportunities."
Peacemaker mentions having seen Matter-Eater Lad eat an entire restaurant. Matter-Eater Lad (whose real name is Tenzil Kem) is a superhero, who is a member of the Legion Of Super-Heroes from the future. He has the power to eat almost literally anything, hence the name. He's been the butt of a joke for years now in the comic book community.
When Adrian is trying to lie to Adebayo about being Vigilante he mentions Vigilante could be a woman. In the comics two female Vigilantes did indeed appear, Pat Trayce and Adeline Kane.
During the musical scene Peacemaker is wearing a Faster Pussycat shirt while listening to House of Pain by Faster Pussycat.
Peacemaker spends a surprising amount of time highlighting that Charlie the gorilla has been stolen from the local zoo. in the comics Charlie the Gorilla, also known as Sergeant Gorilla, appeared in a volume of World War II themed comics called Star-Spangled War Stories. He wanted to be a soldier, and actually taught himself how to salute, wore a uniform, and participated in a show entertaining the troops.