Victory Guided Amnesia: Except for Mike, all of the children completely forget their victory and spend most of the adults' portion of the novel trying to remember. After their second victory, they all begin to forget.
Bill Denbrough (aka "Stuttering Bill"; "Big Bill")
Scars Are Forever: Zig-zagged. Henry cut an H into Ben's belly when they were kids, and a much deeper scar was inflicted on him a little later. The H scar stayed (and became a neat pub story) but the deeper scar faded away after they left Derry. When IT resurfaced and the Losers started being drawn back to Derry, the scar reappeared.
Heroes Want Redheads: All the male Losers are romantically attracted to Beverly at some point, as is Beverly herself to Bill and they all have sex with her - although Ben becomes a couple with her at the end.
Butt Monkey: He grows up as a stereotypical fragile, allergic-to-everything mama's boy, gets his arm broken by Henry and pals, and marries an overbearing carbon copy of his mother.
It's even worse in the movie, where he never stops living with his mom and dies a 40-year-old virgin.
Calling The Old Lady Out: Eddie is pissed when he's in the hospital and his mother sends his friends away. She is actually frightened of him for a moment. Note that this is the only time he ever stands up to his mother.
Giant Spider: Not IT's true form, but probably as close to it as any human is able to perceive.
Hoist by His Own Petard: IT shares the weaknesses of whatever form IT takes. Also, if several people all perceive IT as one form and think of IT in that form hard enough, IT becomes "mode-locked" and unable to change.
Load-Bearing Boss: After IT is finally defeated, a flood destroys much of Derry later that year. It's implied that IT had allowed the town to exist in exchange for providing IT victims every 27 years.
Monster Clown: IT's primary form, Pennywise The Dancing Clown.
Monster Is a Mommy: IT is female and protecting its eggs. Unlike most examples, however, this time it's bad news.
Not Quite Dead: Pennywise appears in other novels featuring Derry, including some set after IT, and is mentioned in the Dark Tower series.
Red Oni, Blue Oni: Pennywise/the Spider and the Turtle. One actively hunts down and eats human children while the other just sits on the edge of forever, seeing it all happen and "helping" the Losers during their first confrontation with It. The Spider berates it for just sitting there, offering seemingly useless advice. That the Spider's eyes are described as ruby-red while the Turtle's shell is some blueish-greenish color also reinforces the trope.
Mean Character, Nice Actor: Jarred Blancard as Young Henry Bowers. According to the DVD commentary he felt really bad for having to use the N word and couldn't be more apologetic to Marlon Taylor (Young Mike) after they finished filming the scene.
Even Evil Has Standards: Victor is fine with beating up smaller kids for fun, but shocked by some of Henry's actions (such as trying to carve his name on Ben's stomach with a knife).
Noble Demon: Not a completely straight example, but, he has some shades of it. He has no problem beating other kids up, but, he will never go as far as to do permanent damage to them. While being chased by Henry's gang before the Rock Fight, even Mike acknowledges that out of all of them, at least Victor doesn't want to do him any serious harm.
Only Sane Man: Victor is among the first to realize just how far off the deep end Henry is going, and likely the first to do so on the bad side.
Red Oni, Blue Oni: Although never acknowledged as equals, he is the Blue to Henry's Red. This is especially clear in the Rock Fight. Henry got hotheaded, and only got himself hurt even further. Victor kept his cool, and was able to take all the damage Henry's Gang suffered, and return it in kind back to the Losers by himself.
Heroic Sacrifice: After killing Victor IT goes after Henry, but Belch defends his friend by attacking It. However, Henry leaves Belch to fight It alone, though It easily overpowers him and tears half of his face off.
Patrick Hocksetter
Depraved Bisexual: Fondles the girls in his class, masturbates Henry and offers him oral sex.
Enfant Terrible: He murdered his baby brother when he was younger.
One-Scene Wonder: His single appearance is one of the scariest things in the whole book.
The Sociopath: Even moreso than Henry. He thinks that he's the only real person in the universe (Solipsism), and the only thing that can excite him is killing and torturing other creatures.
