Recurring
Nick (voiced by Ben Feldman) is Frances' lackadaisical, often oblivious boyfriend who loves VR gaming. Feldman also provides additional voices.
Jonas Backstein (voiced by Danny Huston) is a powerful Swiss financier and board member of Reutical with heavy insider ties to the federal government who is focused on destroying Marshall and the mushrooms.
Cecily (voiced by Sydney Poitier) is a Deputy National Security Director with influence over the DEA who secretly conspires with Jonas and Reutical.
Hildy (voiced by Sue Rose) is Marshall's idiosyncratic, mycologist mentor who seeks to possess the Blue Angel for her own ends.
Sonia Applewhite (voiced by Lin Shaye) is Frances' mother who has been diagnosed with dementia, and is Frances' main motivation for acquiring the Blue Angel mushroom.
Amelia (voiced by Shannon Woodward) is the laid-back mycologist hired by the DEA to gather information on the Blue Angel, also acting as a single mother and caretaker to her ill son, Wyatt. Woodward also provides additional voices.
Kiki (voiced by Christine Ko) is a researcher at Reutical. Young and knowledgeable on medicine and the pharmaceutical system, she acts as the devil's advocate for the company, disputing the arguments brought up by people such as Marshall.
Zane (voiced by Alan Resnick) is Marshall's self-trained herpetologist half-brother specializing in marine animals. He enjoys taking psychedelic drugs and illegally imports rare tropical animals.
Jimmer Jarvis (voiced by Mike Judge) is the Sheriff of Averesboro, North Carolina who becomes Marshall's next-door neighbor and ally.
Rusty (voiced by Steve Hely) is Jimmer’s redneck nephew who spends most of his time shooting guns or riding his BMX bike.
