Tony says that Dom isn't just a gambler, he's the gambler. The Gambler is the alias of Becky Sharpe's father Steven Sharpe in the comics.
This episode proves all the Bus Metas are indeed alive; Null was in Cisco's Who's Who? Binder along with Fiddler 1.0, whom Barry and Iris confirmed was alive when Andrea Wozzeck took the mantle.
The comment that Dom is "the gambler and all he needs is a roasted chicken" is a nod to Kenny Rogers - singer of "The Gambler" and namesake of a restaurant chain specializing in rotisserie chicken.
When Khione works with Chester and Mark to test what abilities she has and tries to see if she has cryokinetic powers, she says "Ice blast activate!... Go ice, go!" which may be a reference to Spider-Man (2002) when Peter Parker is trying to figure out what makes his web-projection powers manifest.
This features the return of Becky Sharpe who hasn't been seen since Subject 9 (2018), which aired more than five years prior to this. However, Becky's last appearance had actually been in True Colors (2018). In "Subject 9" Becky's body appeared but was being used as a vessel by Clifford DeVoe.