There's a few notable ones for me:
Cr1tikal/penguinz0: I was subbed to him way back before his face reveal, when he just did commentary over shitty indie horror games or obscure/weird vidya. It was a nice little niche, his monotone way of speaking was strangely refreshing compared to most tubers who were over the top at the time. Plus he was relatively unknown, and seemed like a humble guy. This all changed after his face reveal, which didn't bother me at first. (Although I vastly preferred not knowing what he looked like, it was more fun that way). He gradually stopped doing what I originally liked him for, and started doing reaction and drama videos with the most boogie2988 milquetoast takes on everything. I think the nail in the coffin was the iDubbz (I'll be getting to him) cuck controversy video he did, it honestly just felt hypocritical considering if the same thing happened to some content creator he wasn't butt buddies with, he would've torn into them. But no, iDubbz was his bestest buddy, so obviously anyone who calls him a cuck or simp must be some unhinged individual. Couldn't stand him after that that and stopped watching his ass. Glad I did after that whole Pokemon card craze where he was putting down absurds amounts of money for a stupid children's card game and his girlfriend walked in and told him to stop spending his money on stupid shit on one of his streams and he was like "woah babe, you're like ruining my vibe". Jesus H. Christ that was embarassing. Also he looks like a greasy teenage skater boy with the long hair.
iDubbz: Discovered him through his Kickstarter Crap series and had a lot of fun with those videos, especially the ones where the kickstarter author would respond back. He wasn't that big back then, and his humor felt unfiltered. Then he got huge doing his Content Cop stuff, and those were a great time as well. But after a while, he slowed down with his uploads, and that's not a huge deal for me, I can wait if it means the next video comes out is higher quality. Anyways, he uploaded that "idubbz is a simp??" video or whatever the fuck it was called, and I've never seen someone's mask fall off so hard. You could tell he was definitely upset because his face was beet red at the end of the video, and was lashing out at much smaller tubers than himself, which was ironic since he used to do the opposite with the content cop vids. You think someone like him would simply laugh off the people calling him a simp/cuck but nah, he had to explode. Couldn't watch him after that tantrum, and watching him and Anisa go downhill has been very entertaining over the past couple years.
SomeCallMeJohnny/BrainScratchComms: Discovered Johnny through BSC, which was a commentary group of a few guys, Nayrman (Ryan), SolarisParadox (Lewis), ExandShadow (Ted), and SomeCallMeJohnny, and they'd occasionally had special guests on. One of them would record a series of videos of them playing through a game on a separate channel, and then they would watch and commentate over the playthrough. I'd love the playthroughs that were godawful (Ted's The Legend of Zelda playthrough) or had a really embarassing gaffe (Johnny dying to Storm Eagle in Mega Man X, who is considered to be a braindead easy boss) because they would just tear into one another or slowly go insane. After a while I just got bored with them and stuck to watching just Johnny since he was easily the most charismatic and down the earth of the group. He'd just review games on his own channel, nothing too special but the way he carried himself made them a joy to watch. Eventually I got bored of him too, but didn't unsub. Then COVID happened, and holy shit, something in him snapped because he would always end his videos like patronizingly preachy shit like "wash your hands, wear a mask!" or "get the vaccine!" and he even did this at the end of a crossover video he did with Caddicarus. He just came across as holier-than-thou asshole, and I couldn't stand him anymore so I cut him out completely. Good riddance. Did the same with BSC, since they drank the same Kool-Aid as Johnny, especially Lewis and Ted, and I hadn't watched their crap in over 2-3 years anyway. I honestly don't care where people stand on the COVID stuff and the vaccine, but I can't stand people who act like they're on the right side of history and everyone who disagrees is an unwashed troglodyte.