In "The Secret Box", SpongeBob's suggestion that Patrick might be "a deranged maniac who keeps his victims severed heads in a box" is a reference to the film Se7en (1995).
Right around the 2019 Super Bowl was about to take place, fans petitioned for Sweet Victory to be played during the halftime show as a tribute to series creator Stephen Hillenburg, who'd just died from ALS. Fans were disappointed when only a small animation of SpongeBob and others were in uniform was shown but the song wasn't.
When SpongeBob puts a stocking on his head, he briefly squishes into the shape of a woman's leg.
In "Band Geeks," the Bubble Bowl "real-life" crowd is footage from a USFL Tampa Bay Bandits vs. Memphis Showboats game at the Liberty Bowl Memorial Stadium in Memphis, Tennessee, back in the early 1980s.
In the German dub of "Band Geeks", instead of a Sedan, Patrick mentions an Opel Kapitän (Captain). The Kapitän was a make of the German brand Opel, and it was manufactured from 1938 to 1970.