The show has a lot of world-building, a lot of strong guest stars, and a definite sense that there is a lot going on outside of what the (relatively small) core cast see.
WARNING: Spoilers are unmarked.
- Theo, who begins the show as a hated enemy of Thunder Mountain who slowly becomes their ally, spends much of season one fighting a largely offscreen fight for control of her town. She ultimately wins, despite being the underdog at times.
- The two-part finale of season 1 and the two-part pilot of season 2 reveal that Devon, Ezekiel, and Lee Chen have spent most of season 1 trying to keep the Valhalla Sector from bringing back the Big Death or coming to Thunder Mountain, with their efforts rarely being shown and initially seeming Ambiguously Evil.
- Throughout season 2, there is a resistance movement against the Army of Daniel operating inside their capital, led by Action Girl Rachel. However, the group only appears twice, when circumstances bring them into direct contact with Jeremiah and his friends.
- At the end of her sole episode, Girl of the Week Claire sails to Europe to find out what kind of remaining society there. Her solo trip across the ocean and what she finds in Europe are left to the viewers imagination, but certainly aren’t boring.
- Simon, the Thunder Mountain agent who sends Jeremiah and Purdy to the outpost before dying, has several informants who fit this role.
- Jimmy from "The Bag" was voluntarily experimented on to make a vaccine (possibly by The Valhalla Sector) and is slowly dying as a result.
- Eddie from "To Sail Beyond the Stars" is a quirky Knowledge Broker who (aided by a man named William) has been trying to track down information about a mysterious group of people who are burning settlements.
- Farralon from "City of Roses" has been trying to make a vaccine for the the Big Death, although it’s all but stated that either the Valhalla Sector is manipulating him or he is Evil All Along.
- The two-part season 1 finale features both The Brothers of the Apocalypse (a group of adults who survived the Big Death and have secluded themselves in a monastery) and a Conspiracy Theorist named Wylie who has accurately pieced together the Valhalla Sector's entire origin and Evil Plan.
- Blind Seer Damien from "Tripwire" is the son of a woman who was in the last stages of her pregnancy during the Big Death but still managed to give birth to him and find kids to take care of him while she was dying. Given the implications of how often his prophetic instincts have served his community in the past, Damien himself might qualify for the trope himself.
- In "Things Left Unsaid Part 2", Wylie mentions that four of the twelve previous people he told about the Valhalla Sector and the Big Death tried to do something about the villainous plan but were murdered and five more disappeared (of the other three, two killed themselves and the last leads the Brothers of the Apocalypse).
- Thunder Mountain scout Shashona only appears briefly in "Man of Iron, Woman Under Glass", but mentions traveling across the country, teaching struggling communities how to hunt and farm.
- The first few episodes of season 2 mention that several regional leaders escaped from the Valhalla Sector trap in the season 1 finale and are on the run for that time period.
- Every town (even ones led by villainous characters) featured in the show is led by someone who had to go to a lot of effort to make infrastructure and supplies last for fifteen years while gathering people together during or before the series and surviving in the post-apocalyptic world. Michelle from "Mother of Invention", Kwame from "Moon in Gemini", Samuel from "Tripwire", an unnamed Social Darwinist from "Journeys End in Lovers Meeting" and Theo stand out in this regard.
- Gregory from "Ring of Truth" is a Circus Brat who managed to keep the circus functioning with some other kids after all the adults died and has also been raising a daughter born out of Teen Pregnancy while keeping an eye out for her Missing Mom during their travels.
- Jeremiah talks about how many states with warmer climates are prospering through agricultural means, although the limited amount of fuel keeps the characters from traveling that far from the midwest to observe those efforts.
- "The Mysterious Mr. Smith" features a group of escapees from a Daniel-run labor camp who broke out of the camp for the purpose of exposing the atrocities at those camps at some point before the beginning of the episode.
- "The Mysterious Mr. Smith" briefly features a group of people who travel across the country, memorizing an oral history of what has happened since the Big Death. One of the subjects of their project, a Long-Dead Badass named David, also counts, as he is well known for saving scores of people during the accidental burning of the first city to be destroyed by a natural disaster after the Big Death, and then went on to die heroically saving more lives during a later catastrophe or battle.
- "The Face in the Mirror" reveals that Dr. Frederick Monash spent fifteen years planning the creation of a government to challenge the Valhalla Sector, both inside Raven Rock and after escaping from the bunker, and then built it into a major army capable of challenging The Remnant of the U.S. government. Sadly, his efforts turn out to be All for Nothing when his organization is corrupted and Thunder Mountain defeats the Valhalla Sector without his help. After this, he sets out to defect and help stop the group that he built. Nonetheless, he only appears in one episode.
- In "The Face in the Mirror", Frederick encounters a group of resourceful nomads who have been living in the woods near Daniel while avoiding and loathing his government.
