When Sabrina, Harvey and Ros are talking in the school yard at a dining table, Sabrina is holding a vintage 1969 thermos from The Archies lunchbox.
When Sabrina tells Harvey that Salem is a stray and she's taking him home, Harvey comments he didn't picture her as a cat person. Kiernan Shipka, who plays Sabrina, is allergic to cats.
In the car scene Ms. Wardwell says that she'll "call Dr. Sapirstein in the morning." This could be an homage to the infamous occult film, "Rosemary's Baby, " with the aforementioned character's same name.
When Sabrina and Ambrose are talking on the porch Ambrose is holding a laptop computer. It is the only computer ever seen throughout the first season of the series.
When Sabrina is offered the herbal drink near the beginning of episode 1, one of the ingredients is "tannis" a fictional herb referenced in Rosemary's Baby.