"I'm not the red shirt", as said by Winn, refers to Star Trek, where the men wearing the red shirts always die on away missions.
The episode title "Supergirl Lives", directed by Kevin Smith, comes from a canceled Superman film known as 'Superman Lives' which would have starred actor Nicolas Cage as the title character and Smith was the screenwriter. Tim Burton was set to direct, and even began production, but after complications with the script and the studio, Warner Bros. pulled the plug. See The Death of Superman Lives: What Happened? (2015).
Features an appearance by a Dominator, the alien race featured in "Invasion!", the four-episode crossover with Arrow (2012), The Flash (2014), and DC's Legends of Tomorrow (2016).
Jo Gunraf is cooking a Thanagarian Snare Beast, another reference to the unproduced "Superman Lives" film that Smith wrote. In an infamous story, the film's producer wanted a giant spider in the movie's third act. Smith came up with the concept of a Thanagarian Snare Beast, as he questioned the sense it would make for Superman to fight a spider, regardless of its size.