Noone that i watch died, but often i have come across announcements posts by relatives/friends that someone has died and those blow up a little because well, people send heartfelt messages and then the post gets pushed around because of high replies or someone i follow replies to it so i see it. People dying in accidents, stroke/seizure they never woke up from, illness, suicide.
I would check their accounts, clips, vods out of curiosity i guess. A very strange feeling exploring their content, finding out their songs or art and hearing their voice and laugh, someone i never watched before or knew at all and im only finding about now after they died. And knowing that was their last piece of art, their last song, their last game, and nothing else will come from them anymore. Some were making big plans for new models or events or collabs, they had recently put out a schedule for games they were gonna play that week, new games to start or games to finish. Plans never completed.

I know it will hurt a lot if or when it happens to someone i watch and have known for a while but the scariest thing to me is those people that dont have a close relative or friend that can make an announcement for them. If some vtuber dies and none of their real life friends or family know about their vtubing stuff, or their online friends cant find out about it. They will just stop appearing online one day and people will never know what happened, just keep waiting without ever getting closure. Thats terrifying.