The Rookie - Easter Eggs & Hidden Details

Throughout the series, several actors from Nathan Fillion's previous hit shows make guest appearances. These include Alan Tudyk and Sean Maher from "Firefly," and Jon Huertas, Seamus Dever, and Molly Quinn from "Castle." These appearances are fun nods for longtime fans of Fillion's work and highlight the strong relationships he maintains with former castmates.

Pete Davidson has a recurring guest role as Pete, Nolan's wild and irresponsible younger half-brother. The characters' chaotic dynamic provides comic relief and a glimpse into Nolan's life before he joined the LAPD. Fillion and Davidson met while working on the film "The Suicide Squad."

The show's main title card often changes its appearance to match the tone of the episode. For example, in darker, more dramatic episodes, it might appear gritty or in black-and-white. For the 100th episode, some letters were highlighted to reveal the number "100." This subtle detail reflects the creative and sometimes playful nature of the show.