if you like KH i have a rec on the "character being trans is not the focus of the fic" list I can give you. (trans-mas, but the reason it comes up in the fic is STOP TRYING TO DO EXERCISE IN A BINDER ON A TROPICAL ISLAND WHEN YOU'RE NOT USED TO THE CLIMATE, DOOFUS and it's very casual about it.)
I suspect "always transmasc" is because so much fanfic is written by cishet girls, and a) they know what it's like to have a double X chromosome and b) they want to write about hot boys. That and the popular characters are almost always male-presenting.
oh yeah i cant rly complain about 'all transmasc' bc all i do is transmasc characters BUT why cant someone OTHER than me give the ladies some love
Oh God. Those. Especially when it's in a fandom where I can't imagine that the characters would be whichever one of those things is appropriate.
In a similar vein, people giving bad people the fic's designated bad opinions, regardless of whether or not it makes sense for the character in question, ex that one fic I read way back when where Vriska was homophobic. Like, please. Christ, let your characters be characters in their own rights. Also similar, kinda? That one thing where everyone is trans/queer and nonwhite, with all these painstakingly exact little labels, like "Amethyst is a pangender demiboy demisexual lesbian of mixed Lebanese and Scottish heritage", and then the Bad Dude is just, "Whitebread the cishet white dude". As a shitty bisexual trans dude, I feel personally insulted when people pull that kinda shit. I'm allowed to be kinda petty and terrible, fuck you. Let me have my petty terrible queers.
Using Christian values for a religious organisation in a 'verse where Christianity is not a thing as an excuse to make the characters homophobic. That one gets to me. Especially since at the time period the one I'm thinking of is based on it wouldn't really have been that much of an issue anyway.
Can I add the related "importing a very shallow and simplistic paradigm of misogyny that doesn't match what's seen in the setting in canon just so a female character can Triumph over the Evil Sexists"?
Please do add it. Another thing; casually throwing in extreme kinks and/or serious issues. Goddamnit people don't fucking do this. Well, with extreme kinks it's kinda funny, but it's going to alienate the audience because it's not in enough detail for the people who like it to be interested and people who don't like it are going to be squicked at the mere thought. SUDDENLY ONE RANDOM SENTENCE OF SCAT FETISH! But with the serious issues, it's not funny. One sentence a paragraph from the end about your female lead miscarrying a deformed incest-baby and having her carry on as if nothing at all happened is offensive on just about every level it's possible to be offensive on.
If it wasn't the extreme ones, I could see some of that being like how I've seen multiple people crack jokes about how E.L. James does not appear to be aware she has a foot fetish, but I'd think that's hard to miss with something like scat.
Was loss.jpg the last-but-one strip of the comic's run and did the one after it show the characters the next day laughing it up as if nothing had happened?
It was not and I'm actually not sure what the next one was, but at the very least all the ones before it were formulaic ~wacky comedy~. It also didn't involve incest, though. :::PPP
I'm fortunate enough not to have encountered this one in the wild, but several years ago I was linked to a fic (I can't even remember the fandom, might have been Glee) in which autism was cured by having a foursome. The fail still haunts me.
When I'm searching for fic about asexual characters, I'm searching for fic about asexual characters, not 5,000+ words of (A) and (B) being very much not asexual at each other, plus a single sentence about (C), (A)'s canonical love interest, being aro/ace, used as an explanation for why (A) and (C) aren't together. (I mean, as far as methods of "eliminating the competition" goes, I suppose it's kinder than killing them off. But tagging the fic with "asexuality" for that one throw-away line is just getting my hopes up for no reason!) Also, I know the hair-colors-as-descriptors thing has already been mentioned, but one of my fandoms has a purple-haired character, and certain authors think they are very clever for referring to him as "the violette"...
And it's always "-ette", too, idn't it? And dudes getting called blondes and brunettes and shit. Real obnoxious, that.