The radioman only appears for a brief section of the book and doesn't even get a name, but is one of the more popular characters due to his But I Read a Book About It skills in flying a helicopter.
Dennis only appears in the last quarter of the book, but has lots of fans for being a Handicapped Badass who manages to find his way to nearby towns and survive multiple triffid attacks after losing his sight, when most blind characters need a sighted guide to do that well.
The Triffids and their feeding habits; even in the movie version they manage a few unsettling moments.
Just as terrifying is the blinding. Thousands of people die horrible deaths, because they looked up. And who wouldn't have that night?
One-Scene Wonder: Beadley's presence, actions and influence are felt strongly throughout the novel, but he himself is The Ghost after a couple of chapters in the first half of the book, only having two or three scenes in total.
Strawman Has a Point: As villainous and crazy as Torrance's ideas are, his faction is the only one who keep large amounts of blind survivors alive in the long-term.
In a functioning society with intact civil institutions, sudden blindness could be dealt with; in a post-apocalyptic society with marauding criminals and flesh-eating monsters, blindness would be an insurmountable handicap.
The Woobie: The unnamed teenaged girl in the group of blind people Coker assigns Bill to. She gradually realizes how he might leave them to fend for themselves as he becomes The Fettered. She desperately begs him to stay and keep them alive, and is frightened enough to offer him her body as an incentive. Then, as soon as he turns down her offer but stays anyway she gets infected with the plague, leaving her in enough pain to beg for a Mercy Kill.
The 1962 film
Just Here for Godzilla: Fans unimpressed by the triffid designs and how little of the book is adapted might still be interested in the Adaptation Expansion scenes showing what happened to people on ships, planes, and submarines.
In a scene near the end, the characters shelter at the top of a lighthouse while a Triffid's tendril crawls up the stairs towards them. Unfortunately, it's quite obvious that the tendril is a sock puppet.
The Triffids themselves were basically giant sunflowers. SUNFLOWERS.
