I've noticed these types of fans a lot.
Success stans: there are the fans that will stan a group cuz their group is "the best". They are obsessed with the superiority complex of "my group is the best and they're better than your group" so much that when their group doesn't do as well they will have a nervous breakdown. They will grasp at straws to either make excuses or drag other groups down. This happens because they don't care about the group, they care about the superiority complex that group will make them feel. Like they're better than everyone else cuz their group is better.
Bad akgaes: Now there can be good akgaes but not talking about them. These fans are similar to the success stan in that they are obsessed with their member being the best and or being "mistreated" by the company. Sometimes the mistreatment accusations are true but either way hating on other members doesn't help. A bad akgae is just inherently illogical. Their stan is in a group, hating on other members, and sewing discord in the fandom doesn't help their bias. Why would you want the group your bias is in to fail?
Fantasy stans: These are the stans who are a stan cuz the group/bias member fulfills a certain sexual fantasy of theirs. These are the people who either make erotica of their group/bias and deepfake porn or partake in consuming it. They're the worst cuz they don't see the group as human beings but rather as a sexual fantasy to partake in. Cuz if I cared about a group the last thing I would do is consume porn made with their image and without their consent. Most fans don't wanna admit this cuz they consume fan fics on the regular (which automatically puts them in this category) but the truth is the truth. Fan fics arent bad in general cuz some of them are non-sexual and that's fine. But the sexual ones are not.
Anything else that I missed? Comment below.