There is really only 1 that I keep rereading,
Embers by Vathara. Avatar the last airbender.
Its got a mixed review, but I am firmly in the "its awesome" camp. It mixes in anthropology with true culture clashes and good character development. On the con side it has characters acting painfully stupid. And though most of them learn their lessons, not all do.

 

I'll always love FF7/Crisis Core, so I haven't outgrown the fandom, but The Fifth Act stands above every other fic in the fandom. Give it a reread every once in a while.

https://www.fanfiction.net/s/5951824/1/The-Fifth-Act

 

In my experience, the stuff worth re-reading are always the ones that are well written aesthetically, as opposed to the ones whose main draw was the thrill of the plot. The former is forever delightful; the latter, a one time high.

So, stuff that I consider the former, and which I've re-read, sometimes even more than once:

Game of Champions
Hammered Down
Gentleman of Weapons

Also, not a fic, but I remember re-reading The Devil in G, and it was so much more emotional an affair than the first time through, so much so that the epilogue actually made me shed manly tears.

Further: there are some stories (e.g. Madoka) that by design are better on the second read/watch through, because your knowledge of the story's driving secret makes every scene and every action all that more poignant. It's kind of like the difference between chilling out with a friend when you're both in high school, vs your adult self being transported back in time to relive it a second time - you value it more the second time around, for now you know how precious your youth is; how little time you have together before everyone grows up and moves away; how the future promises nothing better than the innocence and intimacy you already have, and so on.

 

Blank101s' trilogy. Can't seem to get tired of it.

 

off the top of my head (and sorting my ff favs from oldest to newest and browsing...)

The Snow Raven by Krista Perry (of the Hearts of Ice fame) is a fairly short Rurouni Kenshin fic of the events of the Revenge Arc's flashback from Tomoe's POV. Short, sweet, a nice glimpse into the mindset of a kuudere.

Frozen Sky by Jedi Bodicae is a Bleach prequel focusing on an imagined history for Hitsugaya. Shows the whole 'child prodigy' aspect much better than canon ever did. Part of the reason I stopped following the Bleach manga was because poor hitsu could not catch a break, and then i realised i was comparing it to what i read here. Incomplete, but the latest chapter comes after the close of an arc so i just treat it as 'completed' in my head.

Big Human on Campus by Black Dragon6 is a Ranma 1/2 x Rosario+Vampire cross. It's a humor fic that never takes itself seriously. Ranma is fairly OP but power levels aren't really the point of the fic so i find it more than tolerable. Notable for partially being a multi-cross, as a number of students and teachers at Youkai Academy draw inspiration from various other media and games.

The World's Greatest Chunin Exam Team by Dane Namor is a Naruto humor fic. Post series the Hokage has JUST realised he never ever got promoted from genin and sets out to do something about it. If this isn't the first iteration of this concept, it's at least the first I ever heard about and the one i like the best. Describing anything more prolly spoils the experience.

Hitchups by Antic Repartee is a How to Train Your Dragon fic. Astrid's discovery of Toothless leads to much misunderstanding and Hiccup decides to flee Berk rather than face the rest of the village. Completely derails the canon plot and moves Hiccup into a wider world semi-based on the source materials, partially on legend, partially on history. A pretty epic read imo, and complete!

Game Theory by immatrael is a Nanoha for want of a nail. Precia is still obsessed with Alicia and the Jewel Seeds, yet remains somewhat sane and pragmatic. So when she discovers that someone is competing with Fate over them... well, KILLHERKILLHERKILLHER is supplanted by something a bit more insidious... The plot is derailed fairly early, but still parallels canon up to the final act. This fic covers season 1 of MGLN, with a sequel Power Games (not complete as of yet, but maybe a chapter or two from an epilogue) finishing up season 2.

Making Magick by Mashadar takes the common Zero no Tsukaima's fanfic cliche of 'Louise summons X' and inverts it to hilarious results. Crosses with Magicka of all things, is unashamedly crack and i love it for it. 'Nuff said.

 

Well, there are a few of those stories for me that I re-read from time to time or I already know I will at a later point.

Except for the story at the very end, all the rest are links to the DLP library threads.

Victory at Ostagar I must have read three times by now. It has become the Dragon Age fanfic for me. It incorporates elements from the first two games (it was finished before Inquisition came out) and speaking as someone who loved the first game, this fanfic really eclipses the game by a longshot. It does it so much, I still have zero interest in playing Inquisition any time soon, knowing that I have gotten all the closure on Dragon Age that I want with this story. It's weird, no other fanfic did this to me, left me so satisfied that I basically stopped looking for fanfics of it.

Don't think Dreaming of Sunshine needs much discussion but yeah, have revisited this story several times over the years as well.

There are a bunch of Naruto stories in general that I have read a few times, could easily be a list on its own and pretty sure most of them are in the libary but special mention, I think, needs to go to The Girl From Whirlpool, for just being so damn good that I think everyone who has read it basically considers it canon for them. Just an outstanding story on every level and it is such a shame it was abandoned.

Cyberwraith9's Ascension Teen Titans trilogy I go back to periodically as well. Just a phenomenal story, feels rather Worm-esque before Worm was a thing. A huge pity the author didn't finish the third story but he did update one of his other stories a few days ago, so he is still alive and writing, so one day he might return to it.

He Who Fights Monsters I've read a bunch of times as well, even though I have not touched a single other Rosari+Vampire fic (or the manga/anime), knowing none of it will even be half as good as this one. Pretty sure that the best way to enjoy this is by knowing as little about the source material as possible. Really, the author needs to file off the serial numbers on this and do something original because I can't imagine this being too tied to Rosario+Vampire in a meaningful way. The idea of a monster school is easy enough to adapt.

Of Sheep and Battle Chicken I have read through twice already, despite its length. It's not technically the best Mass Effect story out there, there are a few who are technically better, like Interstitium but this is easily the most engaging, the most interesting and the most memorable one for me at least.

Queen of Sorrow is a Fire Emblem fic that is criminally underappreciated in its thread and needs way more love. I've read this as someone who has never played any Fire Emblem game and knows virtually nothing about the source material and I loved every second of it. I can only imagine someone with that knowledge will get even more joy from this.

Four Deadly Secrets is by far the best RWBY fic I've read and I am deeply saddened that there haven't been any updates in a while. Still read smashed through this twice.

These are stories I have read only once, but where I know I will reread them over the next few years whenever I find the time/energy for it:

The Camera Loves You by Asynca, an excellent Tomb Raider fic, plus sequel. Also best in the fandom, imo, bar none.

Puella Magi Homura Magica is an excellent story for PMMM fans and a great continuation with great characters and awesome conflict.

Fargo is the other outstanding PMMM story, this one focusing more on OCs though.

Like Cats and Dogs by disnickyX. So, yeah, I know this will probably not be a huge hit on DLP, seeing that it is Victorious fanfiction but I fucking loved this one and I know I will reread this more than once in the coming years. The standout part of this is easily the family drama in the West family where the relationships are just so compelling and fleshed out that it is amazing to behold. Jade's relationship with her step mother and her sisters and how Tori fit into all this and how Jade herself was explored, all of that worked really, really well.

There are a ton of other stories out there, that I just can't remember right now but will come to me later but I don't want to make this too long.

 

I'll second He Who Fights Monsters. It's a story worth a re-read everytime.

The Metropolitan Man is also an amazing story which I find myself reading again from time to time. It's a Superman story with Lex Luthor as the protagonist.

 

Alright, these are all pretty short but they were memorable and amazing for how much was started.

https://www.fanfiction.net/s/7281191/1/Freedom-in-the-Eyes-of-Another
A dark twist on what should've realistically happened on Team 7's first mission

https://www.fanfiction.net/s/10027415/1/Kaze-no-Uta

SI falls into Avatar world, again realistic.

https://www.fanfiction.net/s/10213324/1/The-Natural-Habitat-of-Haruno-Sakura
Humourous real world AU from Sakuras POV, very long.

https://www.fanfiction.net/s/8998604/1/Troublesome-Discoveries
Time traveling dimension hopping, a Katekyo Hitman Reborn fanfic that I would call one of the best in that fandom, too bad it hasn't updated

https://www.fanfiction.net/s/5097905/1/Mirrored-Images
Another Sakura story, She time traveled and it turned out different then she thought fun twist.

Know a lot more really good ones that I've reread once in a while but these are the one's I reread most often. Not to say the other stories are bad just that I have a good memory so the plot twists aren't engaging enough for me to reread to many times. I'd put Other Gods, Dirt an Ashes the one and a half body problem, Beneath, Crying Wolf, Brave and Kind.

 

I've reread Polarity and Shocker: Legit semi-regularly.

 

@Nemrut @Xandrel

I think He Who Fights Monsters is a contender for best fanfic in any fandom, but I disagree about it being especially worth re-reading relative to the value of the first read through.

The main draw of the plot was that you felt and lived Tsukune's claustrophobic, fearful existence, along with the sheer unpredictability of how things would turn out. On the second read through, however, you don't have the latter, while much of the former is degraded, since familiarity breeds comfort - having "experienced" such a surrounded-by-monsters life-threatening situation once, it's less novel and far less frightening or claustrophobic. And, since the story wasn't particularly aesthetically pleasuring, I don't think it's really all that great a story to read again.

I tried, but it really doesn't have the same charm or intensity that second time through.

 

I don't see this talked about very often, but Hammered Down was absolutely enthralling. I usually think that 500k words is too long for a fanfiction, but I really breezed through this by my standards. Best Bleach fanfiction out there, in my opinion, though I haven't exhausted Bleach as throughly as Naruto or HP.