Angst? What Angst?: A lot of loopers manage to get over their baseline problems rather quickly once the loops start. Either because they eventually become powerful enough to easily deal with what was causing problems, or received help from outside loopers. However, it should be noted that this is a bit of a Broken Base amoung loop writers. Some feel it waste good Character Development potential, which is why a few good out of their way to Avert this trope, while others feel it gets in the way of comedy potential, which is why it's frequently Played Straight.
Archive Panic: That list of loops on the main page is taller than most browser windows.
Taking all loops listed as compiled on the main page, the total number of words written and compiled by all writers is, as of 2-21-15: 3,404,343.
Saphroneth's original fanfic, the MLP Loops, currently leads with 1,389,218 words total, over one third the total length.
As of February 27, 2017: The MLP Loops now have 2,042,068 words total.
Heck, the tropes page got so huge it had to be broken up.
Naturally, how powerful certain characters are in regards to other characters, although arguably even worse in the loop setting due to how crazy powerful all the characters become eventually. Even when characters are powered down thanks to certain loops, there's still a hefty amount of debate over whether the characters could still easily handle it due to being Genre Savvy and such.
There's also the overuse of certain settings in the loops and plotlines common to the loops and settings. An example being Equestria being the dedicated 'heal all problems' loop for nearly all the loopers. Some think it's good because they're use to it by this point, and the most experienced with it. Others don't like it because the 'healing a loopers personal problems from their baseline' plot has been over done to the point of cliché for some, and others feel it wastes good character development potential for the characters of said loop because they couldn't over come it without outside help, and it often only takes one loop for the Equestria loopers to pull it off. note In Chapter 149, this trend is subverted when the ponies come across a problem that can't be solved so easily.
Exactly how the mechanics of characters 'Awaking' for the first time in the loops work is a subject many authors of the loops can't seem to agree upon. The only thing set in stone is that they have to be important to the anchor in someway to start looping. Ask any of the authors about specifics though, and one will likely tell you only characters from baseline can loop, while another will say characters that originate from variants can loop, while others will say variant originated characters can only loop if soul bounded to the anchor, while others say they have to be soul bounded to an artifact that they can stuff in their subspace pocket to survive the loop transition, while others say that's impossible because subspace pockets can't hold sentient creatures, even if they're in a non-sentient object like a Pokeball... And then there are people who say pretty much the only qualification is how popular they are with the readers, and if people / the authors care about them enough to do so.
Darker and / or serious related snips / loops. Especially if your trying to submit it to a more light hearted loops adaption. No matter how well written it is, it will get people arguing about whether it should go up or not because of it being dark, or if the darkness is really necessary. While more serious adaptions or adaptions of works set in a dark universe generally don't mind it, it's not unheard of to hear people arguing about this kind of thing there too, especially if they consider it dark even by their standards.
What is canon? That can get nasty real fast.
To expand on it, this is typically only relegated to Innortal's Loops, which have their own problems, but there's one other point that gets nasty. Namely, certain people think that if they get a few likes, then a snip is canon, while others say that anything not in a compilation on FF.net is not canon, yet or otherwise. Considering the rate at which some compilations update, this can be a source of frustration.
The "nutcracker" incident. Not much is known about it, but it resulted in a movie being watched by non-loopers that was so incredibly terrible it shocked a few of them into looping. Some writers found the idea hilarious and a good way to get non-loopers that wouldn't normally loop looping, while other writers found the idea stupid and refused to treat it with anything resembling canon. To this day, it's status as canon is still up in the air...
People editing the TV Tropes page to update about their own loops / snips. It's divided between the authors who just like editing TV Tropes and what they've written stays fresh in their heads, authors who primarily edit for their own loops and don't see what the problem is, people who don't edit at all because they either can't or won't, and people who feel like other people who don't write for the loop should be the ones to do it because of such things as notability. note It should be noted though, TV Tropes itselfhas no rules against this, but the backlash that usually results in the community when an author goes on an update spree about their loop is enough to keep most authors afraid of posting anything about their loop to the TV Tropes page.
What's the best way to take an axe to the fandom? Suggest a villain as a looper.
Even "better"? Suggest that they should remain villainous while looping. Really, suggesting any new MLEs outside of the establish ones will cause a major stir. Even if they're about as competent as Team Rocket, it will result in Torches and Pitchforks from both supportors and detractors.
Even even "better"? Have a non-looping character prove to be a regular challenge for most loopers. Doing so will not only get you the arguments above, but also arguments over whether the non-looping character even can reasonably present a challenge to any given looper.
Innortal's original loops. Did they have genuine funny moments, or were they mostly perverted teenager Wish Fulfillment? Were some of the original sevens actions in them justified, or were they just horribly written? Should they be respected for creating the loops in the first place or, even though they did, that doesn't excuse how badly written they were? This isn't even getting into about what and which of his loops, outside of the original seven being the first batch of loopers, is and/or should be treated as canon...
The Spacebattles loops. Are they still genuinely entertaining, or have they been dragged down by trying to explain each and every aspect of the setting? Do the rigid rules established for the setting help clear up confusion, or do they stifle attempts at creativity? Have they gone too far with the crossovers and forgotten about the time loop aspect of the setting? Is showing what the infinite loops are like from an admin level a good idea or not?
Canon Defilement: If the TV Tropes thread under the Fanfics Forum for this fic is anything to go by, there are quite a few Tropers on This Very Wiki who see even the post Innortal loops as such, thanks to blatant use of Peggy Sue tropes to the point that the characters barely even resemble themselves after the first several loops.
Some have called the Jojo Loopers as this. In fact, it's possible that the entire setting has reached this level, with some of the writers for it insisting that the only thing that can hurt Stands in the entire multiverse are things that one must get from the Jojoverse, meaning that anybody who doesn't learn such tricks are going to have trouble regardless of how powerful they are.
Pops up somewhat frequently with a number of authors whom have favorite characters or settings.
While pairing characters with each other who aren't in a canon relationship isn't frowned upon, going into explicit detail about their more intimate moments sure is, and is considered the gateway to Jumping the Shark, partially due to the... ahem, styleof Innortal's original loops. That said, there's nothing outright stopping people from writing "Innortal style", though it's not a particularly wise thing to do, and plenty of people who frown upon Innortal style often imply that 'certain actions' do happen with characters who genuinely care about each other in that way.
Various authors have them, which are the quickest way for snips to be declared non-canon if the author runs a thread. This included Darker and Edgier snips on the Pokemon thread, poorly proposed ideas in general, Wildrook's non sequiturs in some cases, and Sunset Shimmer on the Star wars thread. Mentioning Steven Universe in the Cartoon Network thread is also becoming a button.
Villain Loopers. Even though there's a small group who think such a concept could have good potential, a larger part of the loops community grabs their Torches and Pitchforks upon someone bringing it up, regardless of their reasonings.
Harsher in Hindsight: A number of loops. For example, in the MLP loops, Glida's home was a glorious empire. In Canon, it is quite different and Looping Glida essentially lost her childhood hom. In the RWBY loops, there were several snips with Blake and Adam. Then came the expansion showing him to be a monster.
Even in the original Innortal loops, Naruto and Kurama manage to become friends as time goes on. Fast forward to the later arcs in the Manga, where they actually do manage to become something resembling friends. (Albeit, Kurama is a bit of a Tsundere about it...)
The first time that Discord and Berry talked she said she will not even consider dating him, sixty or so chapters later they are.
An early chapter has the cast re-enacting the defeat of G1 Tirek. Flash-forward several dozen Loops, and the Running Gag about Tirek totalling Twilight's library on a constant basis.... And that's not to say anything of the mane cast actually fighting (an updated) Tirek in the actual show later on. (The snip was made long before the season four finale was even a thing!)
Looping Sunset's personality is nearly identical to how she acts in Rainbow Rocks, making this Heartwarming in Hindsight as well.
To clarify: Sunset was activated as a Looper prior to the reveal that Rainbow Rocks even existed. All of her Character Development in the Loops was made without that in mind.
When they start Diamond Tiara looping, the writer make her talent was hard-flanked leadership. Come "Crusaders of the Lost Cute Mark", it's revealed that leadership is Diamond Tiara's true ability in canon.
Memetic Mutation: Given how long the loops have been going on, they have quite a few.
''X'? Why are we 'Y'?' Is a common gag started in the FiM loops where the characters laconically discuss the bizarre and sometime surreal variants they wind up in, like the original gag where Twi and Rarity looped in as cuttlefish.
'"Dammit, people! Stop voting for potato!"
Seasonal Rot: The Spacebattles loops have been hit hard with this over time, as the loops have become less about playing with the potential for comedy in the "Groundhog Day" Loop concept, and more about writing crossovers and convoluted storylines that happen to have time loops going on in the background.
Uncanny Valley: Some Loopers regard nonloopers as disturbingly static versions of their friends and family. On the flip side, young loopers or particularly perceptive nonloopers sometimes regard older loopers as being strangers in the bodies of their friends when they have changed a lot from their baseline selves.
Crossing the Line Twice: While there are debates over whether or not Innortal's loops are good or not, there are few who will admit that there are quite a few moments that manage to be so horrifying and insane that it becomes hilarious; an example being after a few loops where Harry gets fed up with Draco, he decides to retaliate by handing him a live hand grenade, much to Hermione's horror.
Played straight for a minority that feel that the Crack Fic style comedy of Innortal's loops makes up for the more divisive aspects of it, especially when compared to the tamer and overall less comedic Spacebattles loops.
Nightmare Fuel: Implications of the premise aside, the loopers themselves manage to be this as well. They've become so powerful, and yet so bored. So they think of creative ways to pass the time. However, the Time Abyss has resulted in them loosing most of their morals and misgivings. They are no longer the characters we know and love; they are half-insane, unkillable, unpunishable hedonists with severe PTSD.
In general, the male loopers prank each other or people who've annoyed them in ways that would be considered dangerous at best, deadly at worst. The female loopers frequently rape or gang rape the male loopers and non looping characters. And nobody ever stops them, because nobody can.
These factors tend to be what is brought up the most in the debates between what is and is not canon in the Innortal loops.
Revenge Fic: You can tell which characters Innortal doesn't like as well. How much he doesn't like them ranges from indifference (Sai, Tuxedo Kamen), to character bashing (Dumbledore and the Order of the Phoenix, Kakashi), or being brought into the loops either to be repeatedly outclassed and / or humiliated (Akane, Asuka).
Magnificent Bastard: Haseo seems to be shaping up into one of these, with the amount of time he has spent with Shiroe in Log Horizon Fused Loops. Most noticeably is that he used the things he learned from such experiences to gain enough influence in CC Corp to throw Sakaki out of the job he blackmailed them for without very much difficulty at all.
Mega Man Loops:
Nightmare Fuel: The setup for the Megaman Loops. Their universes are so fractured and fragmented by whatever broke Yggdrasil (it's implied that the Megaverse was closest to 'ground zero', and was thus hit the hardest) that the first four loop attempts shown (over 25) broke down, with the last attempt to make Protoman an anchor collapsing in under 10 seconds. And as already shown by the My Little Pony loops, it gets worse before it gets better...
The Crash, and how it started. In a desperate attempt to save the badly damaged Mega Man Loop, the admin begins a merged loop. Things start off strangely enough, with no sign of the bad doctor, but all the robots being labelled "model-letter", leading to Models X and Z, implied to be X and Zero, who utterly destroy several Robot Masters before going down. Then Model V (Vile) shows up. Blues manages to help his brother and sister take him down, and everything works out fine... and then Blues is knocked out, and when he wakes up, he, Rock, Roll and the Unknown Looper are tied up as part of a strange machine. Then something apparently possessing Doctor Wily shows up, announcing that it's going to use them to escape the Loops and become even more powerful. Worse, Blues has encountered this thing before (it killed him in one of his failed Loops, posing as Doctor Light), and realizes that whatever it is, it's not supposed to exist. Then it begins the procedure. Something goes wrong, and the machine zaps Wily. The last thing Blues can recall before everything breaks is reality itself screaming...
Warhammer 40000 Loops
Broken Base: The ponies. The Warhammer 40K Loops were created to move the setting away from the ponies, but whether that's actually succeeded or not is a matter of some contention, given Leman and his brothers turn up with some frequency in the MLP Loops.
Crosses the Line Twice: A lot of events involving Slaneesh or Nurgle will inevitably do this. Particularly putting AIDS in beverages.
Broken Base: Part of the reason the Skylanders branch ended up becoming read-only. In-Universe, it's because of the portal hopping gimmick, but out of it, it was because whenever the concept of it becoming it's own loop was brought up, there were both supporters, those who were neutral on the idea but were interested to see how it would go, and protestors towards the idea who flat out didn't want it looping arguing about it, even if it was so much as a passing mention that it's looping. Even when brought up that wouldn't be chronicled like the Classic and Legend Spyroverses were in the compilation, it did little to quell arguments. Eventually, it ended up becoming read-only, that way the characters could still be used if needed, without arguments over whether it was looping or not.
The beginning of the (non-canon) Fire Emblem loops is this as well. Robin is the anchor, meaning that everything he remembers, Grima does too. Needless to say, Grima gets creative fast, Chrom and Lucina wake up to truly horrible loops, and Robin is trapped in his own mind for ages, watching his friends get tortured and killed over and over again. This setup ends after one chapter, thankfully.
However, this setup is followed by chapter 2, where attempts to stabilize the Fire Emblem loops repeatedly fail due to an unknown factor royally screwing everything up. The major contributor to the problem, Time Travel (ironically enough) is universally despised by every observer, who are doing their best to stop the Fire Emblem universe from looping. They are, unfortunately, Well Intentioned Extremists who will do what they think is necessary to achieve this goal...which means attempting to railroad and outright neuter as much of the random factor Robin brings into the equation. This comes to a head when it's discovered that Morgan, merely by existing, is the one responsible for the looping, and the higher-ups keep rewriting everything in order to ensure Morgan, as we know them, never comes to be, including manipulating Robin's code to the point that they set up an entirely new baseline where Robin is female and married to Chrom. Even the universe's administrators are disgusted by the "solution"note This is described as "morally repugnant"—in short, a Moral Event Horizon. Thankfully, thanks to Robin being a hugeDeterminator who firmly believes in Screw Destinyand one of the higher-ups acting as a Spanner in the Works, the universe begins to destabilize again, and are finally allowed to loop, thus beginning the Fire Emblem loops proper in Chapter 3.
Dio Brando's introduction snip in The Grand Battle of Pelennor. It's heavily implied that he fed all the members of Xcution to his zombie minions except Ginjo and Riruka, sexually assaulted her while her now mind-controlled leader and friend watched, began feeding on her blood, before throwing her body to a Zombie-fied Haku and Zabuza for them to devour. Made even worse when you realize that the Zombies now have a slavish devotion to Dio, so Haku and Zabuza can't really stop themselves from doing the horrible act.
The second Fused Mega Man / Sonic Loop, specifically the part where Sally and Sonic discuss Loops where they were roboticized, especially Sally's. Her friends start vanishing, one-by-one, replaced by insanely dangerous robot duplicates who remorselessly chase you everywhere, leaving her nowhere to run. And finally, Metal Sonic, the one behind all this, who has a truly disturbed attraction to her, captures Sally, and prepares to transfer her mind to a robot duplicate of her. He flips the switch... and the Loop ends. His machine outright killed Sally.
What Do You Mean, It Wasn't Made on Drugs?: Averted. Apparently the loop that Anakin, as Darth Vader, held a 'The View' esque talk show was caused by his coolant being spiked with something, while the Emperor was experimenting with 'dark mushrooms'.
This being in universe, out of universe it's hard to say if there are any loops written on drugs.
Considering a few of the comments by various authors in the forums, it would seem a few were written on at least a lack of sleep.