Game Changer: Storybrooke is a town in Maine where all the denizens of a fairy-tale world were sent by the powerful curse of Snow White's enemy, the Evil Queen Regina and live in an amnesiac state unaware of their true identities. Here, they do not age. The narrative revolves around Snow's daughter, Emma, the very reluctant designated curse breaker. She succeeds in breaking the curse in the first-season finale.
Garden of Evil: The Queen of Hearts' hedge maze, where the walls devour anyone who gets close.
Generational Saga: Snow White loses her daughter, her husband, and her whole world as the evil queen sends them "someplace horrible", the real world. Emma, Snow White's long-lost daughter, is street smart and resents her biological parents for her abandonment. It takes her own long-lost son Henry to bring her back to the family that she never knew and the idea of the enchanted world they came from. And as more of the past is revealed, we find that this saga went all the way to the great-grandparents generation (Cora/Eva).
Cinderella. It appears that she doesn't know the outcome of Rumplestiltskin's story. But she becomes Genre Savvy when the princes reveal the trap for Rumplestiltskin, as she just knows it's going to backfire.
Regina/The Evil Queen. She clearly doesn't understand what kind of story she's in. She's the Manipulative Bastard equivalent of Unskilled, but Strong; she mostly just plows through her obstacles with a combination of magic and hate.
Emma and her gun. To the point of it almost becoming a Running Gag.
Genre Savvy: Both Emma and Henry, given that they're aware of the original fairy tales, to the point where neither has to ask "Who?" when a name like Peter Pan turns up.
Lampshaded in "Witch Hunt" where the Storybrooke residents are under the impression that Oz and the Wicked Witch are fictional characters until they are informed otherwise by Regina. Cue a string of joking references primarily to the 1939 Wizard of Oz film, including a great bit of deadpan snarking by Regina.
This continues in "It's Not Easy Being Green" in which Regina and her allies are able to make an educated guess about the Wicked Witch's game plan due to being familiar with the heart-courage-brain element of the original story, with Regina even referencing the Scarecrow.
In the finale, the brief glimpse of Elsa that we see has her immediately destroying the urn she was trapped in
The latter half of season 3 appears to be moving towards an inversion of this, with Regina, granted for more personal motives than altruism, takes on the role of town protector against the Wicked Witch, especially once she realizes that she is, literally, the lesser of the evils.
Gold–Silver–Copper Standard: Is in use in the Enchanted Forest, as seen in "Hat Trick". The different coins don’t even have names; they’re called 'silvers' and 'coppers'.
Gonna Need More X: Inverted when Charming is tasked to hide a a giant egg containing bottled true love within "the belly of a beast".
Charming: Where is the beast that reigns over this castle? Maleficent: That would be me. Charming: I'm gonna need a smaller egg.
Good Adultery, Bad Adultery: Mary Margaret and David, who in Storybrooke is married to Kathryn. However, they were originally married in the Enchanted Forest as Snow White and Prince Charming.
Regina and the Genie are arguably a subversion of "Good" Adultery. Regina seems to start her affair with the Genie due to her unhappiness over her arranged marriage with King Leopold, which her mother pressured her into. But it turns out she was manipulating the Genie into killing the King.
In "Bleeding Through", Cora briefly does this to Snow in order for her to be able to answer Regina's questions about Zelena.
Great Big Book of Everything: Henry's book of fairy tales apparently contains the entire history of the Enchanted Forest, even though it clearly isn't big enough (especially with all the full-page illustrations).
In Season 2, it is revealed that Dr. Victor Frankenstein's story is not in the book, implying that there are many other characters in Storybrooke from tales that are unknown to Henry.
The third season expands further on its usefulness. Touching it cures Henry of his amnesia, the same way that Emma finally believes him after touching the book back in the season 1 finale. And in the finale, Hook and Emma use it while they're stuck in the past to make sure that they don't undo Snow and Charming's relationship, and Emma's existence by extension.
"Groundhog Day" Loop: In "Welcome to Storybrooke", it's shown that the town was like this. Due to no time passing, every day was the same. Regina (the only one aware of it) is initially happy to have won, but the tedium of it quickly begins to grate on her.
At times inverted, however, as although the town was frozen in time for more than 20 years, recent innovations such as the Internet and cell phones are available in the town. It is also suggested that TV broadcasts from outside Storybrooke are received as well.
Guile Hero: Henry shows some inclination toward following his adopted mother's manipulative tendencies.
Guns Are Worthless: If you're trying to kill a fairy-tale monster, trying to shoot it with a gun never goes right. You'll need to do it the old-fashioned way: with a sword. (See Heroes Prefer Swords, below.)
Half Truth: When Granny tells Red that her red cloak keeps the Big Bad Wolf away/protects Red from the Big Bad Wolf, it is this. It does keep the wolf away... because it's enchanted to prevent Red from turning into the Big Bad Wolf.
Initially subverted with Regina and Henry. While a cursory glance in early episodes would show her as a stern but loving mom who provides material and medical care for a trouble-making, mentally disturbed little boy, the façade is flaking off like cheap paint and keeps getting worse. However, by the second season, it is made clear that Regina and Henry's love for each other is genuine, to the point where Regina forces herself to execute a Heel-Face Turn in order to prove she's a good mother, leading to her making a huge sacrifice in "Going Home".
Snow and Charming in the backstory, before the whole curse thing.
Ella and Prince Thomas, until Thomas disappears (seemingly abducted by unknown forces) anyway. Their Storybrooke counterparts end up getting engaged in Episode 12.
This isn't only true in the backstory now. When the curse is broken in the Season 1 finale, everyone remembers their true identities and all the couples are able to reunite.
Happiness in Slavery: The Dwarves seem to be this as they churn out fairy dust. Aside from someone like Dreamy/Grumpy.
Harmless Freezing: Played straight and averted. When stuck in an ice cave of Elsa's making, Emma begins to succumb to hypothermia and would have died if she wasn't rescued. However, Hans is completely frozen by the Snow Queen and later returns, as does the entirety of Arendelle. "Fall" reveals this freezing curse lasted thirty years, but all Anna and Kristoff can say when released is that it was cold. These at least could be justified since it was "magic" ice and not real ice.
Hate Plague: The Spell of Shattered Sight, a reference to the troll mirror from Hans Christian Andersen's "The Snow Queen", which makes people see the worst in others. The Snow Queen unleashes it on Storybrooke to make everyone turn against and kill each other.
While not the explicit purpose, Lake Nostros can act this way and does towards Frederick. It returns in Season 2. However, the lake dried after the death of the siren, and there was only one sip left, which Charming's mother gave to Snow to restore her child-bearing capabilities.
Neverland has one, with a nasty downside: since its water's healing properties are tied to the magic of Neverland, whoever drinks from it cannot leave. Trying to do so will undo the healing.
Heart Is an Awesome Power: True Love is mentioned many times as being the most powerful magic in the Fairytale World. It is also the way the Dark Curse gets lifted, helping all the characters recover their memories. The trope name is taken literally a number of times as an extracted heart is needed for a particularly powerful spell or curse to work.
Heart Trauma: The Evil Queen, as Henry puts it, has a thing about cutting out hearts. She does it fatally to her own father then non-fatally to The Huntsman/Graham. Later, as Regina, she uses the heart to murder him.
It seems like she has a Freudian Excuse for this particular fixation, since her mother used it on her boyfriend while she was still decent.
Invoked on many occasions in the series, and not just by Regina.
However, in "Going Home," they both make what appears to be a permanent - or at least long-term - turn towards heroism. This is confirmed in the second half of Series 3 when both become effectively heroic (or hero-victim in the case of Gold) with the introduction of a greater evil. Regina allies with Emma and Mr. Gold defies his captor, Zelena, at every available opportunity.
Solidified in "Kansas" when Regina appears to fully become a hero, to the point of gaining the ability to use white (good) magic to save the day. If that isn't enough, Henry outright calls her a hero and Regina even expresses remorse for her past victims. Not that she loses all her bite, as she still threatens to crush Zelena's heart, but nobody's perfect. However, the final moments of the third season finale cast doubt as to whether Regina's change of heart will actually take, especially when Robin finds out that she had Marian killed.
Hook is pretty much firmly on the good guys' team as of the end of Season 2.
Emma: To hell with this! (Drops the sword and pulls out her sidearm)
Which is ineffective. She eventually uses the sword to kill Maleficent.
She tries the gun multiple times in the Enchanted Forest in Season 2 to no effect. The first time attracted ogres to their location with the loud noise, and the second did nothing to said ogres. The third time, Cora magically knocked the gun from her hands.
Heroic BSOD: Snow's reaction to tricking Regina into killing Cora leaves her bed-ridden for days, completely unfazed when Regina comes seeking revenge, and finally going to Regina's doorstep asking for death, being left genuinely distraught when Regina spares her.
In "Going Home", Regina, who by this point in the series can no longer be considered a villain, having undergone a complete Heel-Face Turn, experiences a brief one when she realizes what she must sacrifice to save the town.
Snow White with the apple when Regina promised that she would trade Charming's life for Snow's. And Henry prevents Emma from eating a poisoned pastry by gobbling it and succumbing to the effects.
Prince Phillip allows his soul to be taken by the wraith when he is marked, even though Mulan suggested that she could mark herself and take his place.
Aurora is ready to sacrifice herself for others, since she doesn't believe she can be happy, but thinks they can and should. Snow White and Mulan don't let her go through it, but still.
Likewise, the season 2 finale sees Regina of all people setting herself up for one. Timely intervention by Emma saves her, but it's made clear she was more than willing to go through with it. Henry even lampshades the point. In season 3, Regina appears willing to lay down her life in the street battle with Zelena.
Even more surprisingly, midway through season 3, Rumplestiltskin/Gold seemingly pulls one, Taking You with Me style, in order to kill Peter Pan. The suicide part didn't take, because of the sacrifice of....
...Neal, in order to bring his father back, even if only to identify the Storybrooke counterpart of the Wicked Witch.
Strangely, Regina resisted the urge of becoming evil after her mother abused her for years trying to turn her into a Gold Digger and an Evil Matriarch, when she thought Snow White had willingly handed her mother information about her lover for apparently selfish purposes, accidentally causing his death, and then after Rumplestiltskin got her hooked to dark magic. However, unlike Snow White and Emma, once she hits an apparent Despair Event Horizon, she collapses and stops trying, while Snow White and Emma alwayskeeptrying.
The Heroine's Birthday: This is almost the first thing we learn about Emma on her Internet date. And her birthday wish turns out to be a catalyst to the events that bring her to Storybrooke.
Snow's is shown in Season 2. Considering her mother died on her birthday, she's never been in the mood to celebrate it.
Hidden Agenda Villain: Rumplestilskin's overarching goal is to get his son back and he manipulates everyone and everything to work towards that goal, specifically to find a magic bean that can open a portal between worlds. Only a precious few characters discover this.
Zelena, until "It's Not Easy Being Green" for the viewers, and "Bleeding Through" for the characters. She seeks to rewrite the past so that Cora would accept her as her daughter.
Abigail, Prince Charming's fiancee in the Enchanted Forest, is introduced as a vapid, spoiled brat, but she has her own secret army and is more than willing to help Charming find Snow White since she doesn't want to marry him either.
The Evil Queen and Rumplestiltskin both have some serious issues underneath their hammy villainy. Indeed, as we learn more about their backstories, the less like villains they appear, with both entering anti-hero territory in Season 2 with both possibly escaping villain territory completely by the end of Season 3.
Hide Your Pregnancy: An interesting case. Snow White is not pregnant in the Enchanted Forest scenes from one year ago, but is pregnant in present day Storybrooke. However, Ginnifer Goodwin is definitely pregnant while playing both versions of the character.
"The Tower" finally reveals that Snow was already pregnant in the Enchanted Forest flashbacks, narrowing down the timeline such that by the time Emma returns to the newly-cursed Storybrooke, Snow is very close to term.
Hollywood Density: When Prince Charming's twin brother holds up his sword and King Midas transforms it into pure gold, he shows no sign that its weight has increased, and handles it as easily as he did before. In reality, a sword that size made of pure gold would weigh well over a hundred pounds.
Hollywood New England: Richmond, B.C. as Storybrooke; Vancouver as Boston and New York; assorted Vancouver-area parks and forests for everywhere else.
Hope Spot: In "Good Form" Emma and others are desperate to give Henry some sign, some hope that he can be rescued. Without which he would likely fall into darkness and become a Lost Boy. They do get a message to him by the end of it.
In "Kansas", flashbacks reveal that Zelena was once able to get past her jealousy over Regina. Unfortunately, Dorothy's arrival makes her envy return in full force.
In "Into the Deep" Cora kidnaps Aurora and threatens to kill her unless Emma, Snow and Mulan give her the magic compass.
In "The Queen is Dead" Cora and Regina do the same thing with Snow White's old maid for the Dark One's dagger.
Hot Witch: So far, every witch in the series except Miss Ginger has been attractive. Physically, anyway.
Hourglass Plot: Revealed to be the backstory of Regina and Jefferson. Apparently, he is an innocent friend of Regina whom she lets grow mad in Wonderland and keeps a bit farther from Grace, his daughter, than he would choose to be. She looks remorseful about the trapping in Wonderland, but does it to save her father. Cue to his Fandom screaming and insulting her. Flashback years earlier. Regina is an innocent girl whom Jefferson hurts for personal gain, before his daughter is even born, making her desperate and causing her to agree to listen to Rumplestiltskin. Also, despite knowing that he could save her beloved, he and Doctor Frankenstein choose to let her believe that there is no way. His tragic backstory has just been turned into something resembling Laser-Guided Karma.
Humans Are the Real Monsters: Anton's backstory. He wanted to explore, and make friends. Instead Prince James and Jack take advantage of his generosity to rob him and reduce him to human size.