i feel like wg and transformation stuff is very tip of the iceberg though what people turn into can go some really far places (like what starry-sea mentioned) but others for me would maybe be
-obscure rare pair and all the horrors to go with it
-growth or inflation of "bits"
-feet???
-and the very specific brand of extreme hourglasses (not that one tumblr artist but they're guilty by association)
i gotta say that i feel like shrek and shadow was a very specific start to weird obscure character pairings but then it devolved into stuff like sans understale and nagito danganronpa or goofy kindom hearts and sephiroth final fantasy
also just the general things done specifically to like mario, sonic, mlp and undertale characters....i and so many other people are owed for the stuff we had to see
there's also that one brand of gross out horror or comedy that really goes places so i've got bones to pick with that too
like there's definitely some stuff branded as super weird that's just mildly odd at best but then when you've gone too far you see stuff you wanna unsee and scrub your brain with soap like that one spongebob episode.....
...i can close my eyes and still see some of it