- Absentee Actor:
- Despite being listed as a main, Summer Bishil (Margo) doesn't appear in three episodes in season one. ("The World In The Walls", "The Strangled Heart" and "The Writing Room".)
- Trevor Einhorn (Josh) is missing from several episodes of season three, which is explained in-universe as him retreating from the other main characters.
- Actor Allusion:
- The Battlestar Galactica reference in season three qualifies, given that Rick Worthy, Keegan Connor Tracy, Michael Hogan and Alessandro Juliani have all appeared in both series.
- Margo pretends her lady parts have teeth in order to dissuade an unwanted suitor. Hale Appleman starred in Teeth (2007).
- Actor-Shared Background: Like Penny, Arjun Gupta is from Florida.
- The Cast Showoff: The songs that get performed are a prime example. "One Day More" in the second is one, and then "Under Pressure" and "All I Need Is The Girl" in season three; the latter two are especially vehicles for Jade Tailor (Kady), who is a trained singer.
- Development Gag: The shot of the "Welcome to Vancouver" sign in "Ramifications" appears solely because Vancouver is where the show is filmed.
- Disabled Character, Disabled Actor: Deaf actresses Marlee Matlin, Winter Sluyter-Obidos, and Stephanie Nougeras as the deaf Harriet.
- Fake Russian: Mayakovsky chants a Russian spell in S02E12 with a very heavy accent («Подобное притягивает подобное чтобы составить цельное.» \ Like attracts like to make a whole).
- In S04E11 his accent is so thick, even native speakers cannot understand him saying "Where am I?".
- Separated-at-Birth Casting: Madeleine Arthur (Fray) is physically very believable as Hale Appleman and Brittany Curan's daughter — ironic, considering Fray is revealed to not actually be their daughter.
- The Other Darrin: Laci J. Mailey played Fen in "Have You Brought Me Little Cakes" and was replaced afterwards by Brittany Curran.
- Throw It In!:
- According to Jason Ralph and Hale Appleman, they were given the freedom to do whatever they wanted for several of the vignettes seen in the montage from "A Life In The Day" and quite a few of them ended up in the final episode.
- Several of the cast confirmed that Summer Bishil ad-libbed the line "you really love that sloth, don't you?" from "The Fillorian Candidate".
- What Could Have Been: The original (2014) pilot script had some major changes from the final version that aired, including:
- Kady dies in the fight with the Beast at the end after getting her eyes ripped out, and there is significantly more Body Horror involved with the Beast than just the extra fingers and the moth cloak. The professor teaching the class also dies.
- While it opens on Quentin in the hospital, it opens in his room and the coin trick he does is more heavily implied to be actual magic, and the reveal that it's a mental hospital is done slower and more subtly.
- The Chatwins' story is closer to the original novel, where there are five Chatwin siblings instead of three and Jane is the youngest at only ten.
- Some of the content of the sixth Fillory book is shown, including a mention that the Chatwins' story is much darker than the books have implied, foreshadowing what's found out later.
- Josh isn't in the Neitherlands but is instead a member of Quentin's class and his lab partner.
- Eliot and Margo find out that Julia remembers at her birthday party, after Quentin walks away from her, and tries to convince him to tell the Dean.
- The script also explains how electronics don't work around magic, but the school library has computers that work for checking email and it's confirmed that there's only one pay phone on the entire Brakebills campus.
Trivia / The Magicians