So maybe everything didn't work out perfectly for Harry. Still, most of his friends survived, he'd gotten married, and was about to become a father. If only he'd have stayed away from the Veil, he wouldn't have had to go back and do everything again.
Adults Are Useless: The adults are more useless than usual, but mainly because they don't have knowledge from the future. Harry does sometimes get them involved on purpose when they can help, such as going straight to Dumbledore when Hagrid gets Norbert.
All Therapists Are Muggles: Harry remembers that this was a problem for Cho Chang in recovering from Cedric's death. She'd needed therapy, but had to edit her story because there weren't any wizarding therapists.
Artifact of Attraction: Sirius starts to put on the Slytherin Horcrux ring despite Harry warning him that it would kill him. He manages to stop himself when Harry says, “Sirius, if you put that on then Snape will have to save your life. SNAPE.”
Badass Teacher: Sirius takes over as the History of Magic teacher. The badass part comes with the package.
Big "NO!": Fred and George when they see the Quidditch field is now a hedge and Harry at one of the times Hermione wins fifty points after he dedicated himself to losing the House Cup.
Bitch in Sheep's Clothing: Harry is much more of a Cloud Cuckoolander this time round, causing the general population to view him as somewhere between batshit insane and just full of it, but he's — usually — a nice guy, employing Dumbledore's tactics of destroying his foes through politeness and snark. Sometimes, though, he strays right into Magnificent Bitch territory:
Pansy: (After Rita Skeeter's Pentawizard Playoffs article) Stunningly pretty? GRANGER? What was she judged against — a chipmunk?
Harry: I wouldn't talk if I were you, Pansy. Seeing as I heard you came in third.
Molly:This is much better gossip than last year's 'Albus Dumbledore was madly in love with Gellert Grindelwald.' Honestly, you'd think Rita Skeeter would learn to stop making up such sensational stories. Obviously Dumbledore was struck speechless by the blatant lies and thus couldn't be bothered to deny it.
"How do you know that?" "My psychic scar told me."
Also, this exchange:
Snape: Is there a reason you felt the need to go running off on a suicidal rescue mission without informing a responsible adult, first?
Harry: I did get a responsible adult. Professor Lockhart is a Hogwarts Professor and surely Professor Dumbledore wouldn't have hired him if he didn't have complete faith in him.
Broken Pedestal: While Harry still obviously respects Dumbledore and tries to maintain something of their old relationship, it's also clear that he's aware of just how fallible he is and how many mistakes he's made.
Deathbringer the Adorable: Averted, much to Harry's dislike. In the original timeline, he and Ginny got a rabbit, and she refused to accept his name suggestion of "Mega Ultra Flame Deathsman", instead going with a more standard "Flopsy".
Harry: Wait... Didn't Draco order you not to try to save my life or to try and drive me from the castle?
Dobby: Dobby wasn't trying to save the Great Harry Potter's life nor was he trying to send him away from Hogwarts. Dobby was trying to break Harry Potter's arm.
Family-Unfriendly Aesop: In-universe. Sirius tells his History of Magic class the story of Voldemort's parents and asks them what the moral is; Lavender suggests, "Don't assume the guy you're feeding love potions is in love with you and stop."
Fantastic Racism: Parodied. Luna asks Snape if he is a Living-ist, or someone who judges based on whether or not a person is dead or alive.
At one point, it's shown that even the Weasleys aren't completely immune to the Pureblood mentality when Ron mentions they never talk about their second cousin who's a Squib (and an accountant). Harry notes that it's to Ron's credit that he doesn't grasp why the cousin is an outcast and that he's invoking this trope unintentionally.
Sphinx: Right. Do not worry, though, as I am not permitted to kill you. That said, healers can work all sorts of miracles these days.
Grammar Nazi: Harry trademarked SPEW for his Grammar Nazi organization 'Stop People Abusing Words.' He chose to spell 'Abusing' with an E to be ironic (and make it fit the acronym).
Handwave: How Harry goes back in time is barely explained and goes against canon, but the setup barely matters.
Hard Work Hardly Works: Draco points out that Hufflepuff never comes out ahead because working hard is such an ingrained, defining trait of theirs. “What are they going to do? Do exactly what they're supposed to do MORE?"
Harmful to Minors: Neville kills Quirrel in the Chamber of Secrets and is understandably shaken by it. Harry and Dumbledore try their best to comfort him.
Remus [Dazed]: Aren't...you going to warn me about breaking [Tonks'] heart?...
Sirius: Why, are you planning on breaking her heart?
Remus: Well, no, but—
Sirius: Then she can handle herself. She is well on her way to becoming an Auror, after all; and I'm sure she could castrate you far better than I ever could.
Insane Troll Logic: Harry does this a few times in order to explain how he knows certain facts that he shouldn't know yet.
I Reject Your Reality: In a lighthearted version of this, Sirius chooses to pretend he was in Majorca instead of Azkaban for over a decade. Everyone pretty much goes with it.
And then there's Luna:
"It's not our fault we're not insane," Hermione said, crosssing her arms. "No offense, Luna." "Why would I be offended?" Luna asked. "I've seen your version of sanity. It bores me."
It Amused Me: Much of what Harry does is to avoid the crap that's going to happen, but most of it he does for the hell of it. The main reason he doesn't tell everybody his actual age is that then everyone will then expect him to act like it.
Loophole Abuse: In Harry's fourth year, he was supposed to work with antidotes and "turned in a bezoar again".
Harry: It's kind of expensive, but the look on his face and the fact that he can't technically fail me because the assignment was to find a way to save someone from the various poisons makes it all worth it.
Fred Weasley gets entered into the Pentawizard Playoffs and George wants to enter as well. Solution: Have him change his name to George "Fred" Weasley and both can participate!
Love Potion: Discussed. When Sirius explains Voldemort's backstory and asks his class what the moral is, Lavender says, “Don't assume the guy your feeding love potions is in love with you and stop?", squicking Seamus out.
The Masquerade: At the Yule Ball, Luna namechecks the wizarding world's policy of hiding from the Muggles.
Mauve Shirt: Some readers thought Cedric Diggory was being set up for this, again. "When I was rereading GoF I noticed how ridiculously likeable [Cedric] was. Seriously, it's like JKR did that just so everyone would be sad when he died…" He's promoted to a supporting character. And doesn't die.
Mentors: Lockhart mentors Harry in dealing with being a celebrity. They later give advice to Krum.
Muggles Do It Better: An example appears to explain why Theodore, a Slytherin, is in Muggle Studies. When asked why he was there, Theodore noted that his father learned the hard-way that Muggles weren't as harmless as he thought after being shot on a trip to Las Vegas, and wanted his son to learn as much about Muggles as possible.
There is also why some students begin to use pens and notebook paper instead of quills and parchment.
Never Live It Down: In story. After Harry becomes a participant in the Triwizard Tournament, he complains that the adults are more worried about how he was entered in the tournament and not why:
Sirius: If it were any other student potentially in danger, they would probably be highly concerned, but you go after trolls because you're bored.
“Well, there might have been an incident seventh year during a Hogsmeade weekend when [Narcissa Black] was out with her boyfriend involving a frog, a bottle of pink hair dye, and a trampoline,” Sirius admitted.
Only in It for the Money: Well, Harry's not only interested in money, but he does deliberately project this persona, to the point where he manages to convince everyone that he's not the Heir of Slytherin ... because if he were, he would be profiting off it!
"Remus and Tonks got married?" Harry repeated innocently.
"No, the other last part. The one about Voldemort killing you," Sirius clarified.
"Oh, well he killed me and I had a nice chat with Dumbledore's soul who informed me that just because I was imagining things it didn't make it not real and then I got better."
Sirius just stared at him.
"It gets better," Harry grinned. "Apparently I only survived because of the power of love."
Sirius groaned. "For the record, when you're telling this to other people, try to come up with an explanation that sounds more badass."
Power Trio: Double Subverted. While Harry, Ron, and Hermione become friends like before, Neville is added to the ranks right from the get-go, making them a Power Quartet. However, Ron, Hermione, and Neville end up more of a unit without Harry, making them a Power Trio and him more of the Draco to their Crabbe and Goyle.
Psychic Powers: Harry's main excuse for knowing what he does is that his scar is psychic. Note that he is not psychic — just his scar. Professor Trelawney calls him a Seer by proxy.
Replacement Goldfish: After Mrs. Norris is killed by the basilisk (the only casualty in that incident), Harry and Mrs. Figg send Filch a kitten to Sirius's horror. She's seen working alongside him like Norris had and he seems to like her.
The Rival: Draco, but in a way that is far more friendly than in canon. Neither likes the other's friends and they sometimes don't speak to each other, but generally they are on rather good terms. It may be best described as a cross between this and Vitriolic Best Buds.
Rule 63: Played with: Changing your gender might be one of the consequences of falling asleep during Sirius' classes.
The Stations of the Canon: Harry occasionally uses these to earn money by betting on highly improbable events. The most obvious of these is during third year Quidditch match between Gryffindor and Hufflepuff, when Dementors show up out of nowhere to crash the match, despite not being stationed at the school. Cedric catches the Snitch, at which point Harry gets a large payout from students that he'd bet (through a proxy, of course) about the outcome of the match with.
Stunned Silence: The Death Eaters' reaction when Harry throws off Voldemort's Imperius Curse and proceeds to mouth off at him.
Harry: [Dobby's] apparently gotten it into his head that Hogwarts is a walking death trap and therefore I'm better off with my Muggle relatives and in particular my Muggle uncle who could snap at any time and try and strangle me. Therefore, he sealed the portal to the platform and Ron and I got bored so we decided not to wait for everyone to fix the mess and just fly here.
Draco: That has got to be the stupidest thing I've ever heard.
George: Besides, the Slytherin team apparently couldn't find anybody to spy as they showed up in person. And full Quidditch gear.
Harry: Why in the world are they wearing their Quidditch robes to practice in? That has got to be the stupidest thing I've seen all day.
Fred: All day isn't very long, Harry. It can't be more than ten.
"Harry, you've predicted 'I will be besieged by the general stupidity of the population' three times this month!" "Only three times? Looks like it's going to be a good month then."
Talking Is a Free Action: After being transported to the graveyard, Cedric, Fred, & Harry discuss what to do (in place of 'run like hell') before Harry stands up to face Voldemort's minion.
Trickster Archetype: The first thing Harry does when meeting the Weasley twins (again) is trick them into starting a rumor, stunning them and Ron. He later encourages others to try to lose the House Cup, calling it a "Suck-up" Cup. Then there's, well, everything else he does...
Uncle Penny Bags: Harry both makes and spends money far more extravagantly this time around.
Unresolved Sexual Tension: Harry points out that Ron and Draco's rivalry looks suspiciously like "UST" (Hermione finds it hilarious, while the acronym goes right over Ron's head). He later thinks Ron and Hermione's relationship clearly falls under this as well.
A Wizard Did It: A couple times, when someone asks how Harry knows something, he says it's “Magic” and refuses to elaborate.
World of Snark: Unsurprisingly, given the source material. Harry, of course, gets to do it the most, but most of the characters, even background ones, get a few snarky lines. A special mention should probably go to Neville, given how a few changes in his first scenes make a huge difference between his canon self and what he is like in the fanfic.
Worst Whatever Ever: Sirius calls himself the worst guardian ever after Harry dies again. Harry assures him he couldn't possibly be worse than the Dursleys were. For some reason, Sirius doesn't find this comforting.
Worth It: In a rare serious example, Harry has to tell himself that it's worth it to be obnoxious to Voldemort even when he's being hit by yet another Cruciatus curse.