Oh man, albinoblacksheep was so cursed. So many things my young eyes weren't ready to see, including a poorly drawn cartoon clip of a dog walking in on her humans giving/receiving a hand job lmao. Weird times.
The worst thing I remember seeing on there was a crude animation of a very graphic and violent crime (I'd rather not specify) set to Tiny Tim's "Tiptoe Through the Tulips." My friend and I loved it and sang/pantomimed it regularly, but yeah... That animator was either pretty disturbed or otherwise 12 years old.
For my nightmare fuel, some of the animations from Rathergood (Spoonguard being the one I can't forget) were terrifying.
I have no idea what YTP is, but I spent a lot of time on Albinoblacksheep and reading a bunch of webcomics every day. In the late 90's and early 2000's, I spent most of my time on Neopets or trying to find things I was interested in before Google and Wikipedia existed. It was a lot harder back then.