As already listed, there are some really outstanding examples, when the narrator deliberately or unconsciously twists things totally.
However, don't you think
any character narrator (as opposed to omniscient authorial voice) is going to be unreliable to some extent?
If there's a car accident, and statements are taken from those involved and 5 uninvolved bystanders, apparently they all give a different version of events. My husband and I can spend an evening out with friends and come back with completely different impressions of how someone felt about something / reacted to something.
If you wrote a novel about a married couple going through a divorce, and wrote it from both their viewpoints in alternate chapters, they would certainly see events differently even if they were perfectly normal people with no particular mental or emotional problems.
My point is that we all look at things subjectively to some extent. Sometimes we succeed in being pretty objective, but a lot of our life is seen through subjective sunglasses.
So.... my hypothesis is that
all character narrators are unreliable, to a greater or lesser extent...
Deb