Fire Emblem Three Houses, the game literally has an NPC named “Gatekeeper” who won a yearly Fire Emblem popularity poll with the highest vote count ever.
A lot of more traditional hobby communities like HAM and model aircraft clubs, that want you to take a dozen tests to play with them. Those same communities seem to scratch their heads as to why they can’t attract new members.
Ham licenses make sense. If you screw up, you ruin things for everyone, so you have to make sure everyone who transmits knows what they’re doing. The problem is the elitism, and how many of them look down on anything more modern than vacuum tubes as not being real amateur radios.
I think those only need 1 test to play with them, and that’s because they are regulated by the government. They want people to follow the rules because if they don’t it can come down on all of them.
The biggest one of these that I know of is falconry which requires 1 falconry test, 1 hunt test, 1 inspection, and finding a two year sponsor. Falconry is specifically set up to gatekeep as to protect the sport in the USA.
I grew up in a very conservative Catholic community. Imagine a group where JD Vance and Harrison Butker would be considered mild. If a new person didn’t show up in the right kind of clothes and faux humility, people would make a snap judgement and start gossiping. If the new person were wealthy or had a lot of children (8+) or were in a medical field, they would probably be ok. The single parent mom with two kids who dared to send one to public school for better STEM classes? Lol, she had no chance.
There was a “welcome wagon” type group who were supposed to invite new people to coffee and doughnuts with the congregation in the basement after services. I watched the one invite one family and offer a handshake, visibly retracted the hand to skip over Single Mom, and then extend an invitation to the next family. Ice cold.
Anime - People don't like you when you're into the popular ones.
Video Games - It's everywhere here. If you're into AAA games, you'll never hear the end of it. If you're into Indie games, then you have to be into games like Hollow Knight, Undertale .etc or you just don't know indie.
Metal Music - Fucking hell, you're always going to be snubbed and looked down upon because you're not into Death or Black Metal. Doesn't matter if you're into Iron Maiden or X Nu Metal band here, but you're just not metal until you listen to anything Black/Death. Maybe I don't want to listen to Cookie Monster and Friends.