Snow White is directly inspired by Madoka Kaname, as a sweet, selfless magical girl in a frilly pink and white dress who abhors violence and, more importantly, who survives a carnage of magical girls and eventually rebels again their not-so-innocent employer. Her background is similar as well, having a fondness for classical magical girls and two partners that are stand-ins for Homura and Sayaka. The anime also gives her pink hair, further increasing the visual similarities.
La Pucelle, although to a slightly minor extent than Snow White and Hardgore Alice, he resembles another Madoka character, in his case Sayaka Miki. Like Sayaka, he is a childhood friend of the main character who becomes a magical girl before her, whose magical girl design features a sword, a corset and a suit with dark blue details (as well as a tail... in some form), and who eventually suffers a Heroic BSoD and dies as a consequence.
Hardgore Alice is basically Akemi Homura, being a tough, no-nonsense, gloomy magical girl dressed in dark, wielding an ability that is almost a Story-Breaker Power at first sight, and having an obsessive motivation to help the main character out of gratitude for a small deed in the past. This is especially notable given that Snow White resembles Madoka herself, particularly in the anime, and that their relationship features a dramatic death as a catalyst for character development as well (only that it reverses the roles, with Alice being the one whose death changes Snow White).
Cranberry, being a blond-haired, veteran magical girl who dies by losing half of her body, is essentially an evil version of Mami Tomoe.
Fav is Kyubey in role and personality, being a cute magical girl animal with a matching personality yet a frightening Blue-and-Orange Morality who instrumentalizes the lifes of the title magical girls. This also makes him integrate elements of Monokuma from Danganronpa, especially in his black-and-white character design.
Magicaloid 44's background and ability makes her the magical girl version of Doraemon. Her official description is even a direct Shout-Out.
Just like Fav reminds of Monokuma from Danganronpa, Fal echoes Monomi from Super Danganronpa 2'', a benevolent Good Counterpart to the villainous mascot of the previous instalment powerless to watch as the participants are killed.
When Pythie, Tot Pop, Pukin, and Sonia arrive in B-City, they decide to steal a Plymouth Fury when they're reminded of a movie about a car killing people, a clear reference to Stephen King's Christine.