I didn't know whether to put this in reader or author discussions because it's kind of both.
There are many types of canon events in stories for both readers and writers. Currently, I know of six which include,
SpiritCanon(Author's head)
This is canon stuff only known to the writer, daydreams about what would happen next and what hasn't been written by the author in any format. None of this will be known to the reader-base unless the author says it to them. That said, it doesn't make it canon.
Canon(physical books, Ebooks, Webnovels, author's notes, audiobooks, etc)
This is what is actually codified in writing, either in a book or in notes. There has to be some recognizable authority on it to be canon, IE the author, publisher, or copyright holder can say what is and isn't official canon. There is a hierarchy for those depending on the situation but I don't want to get into that.
HeadCanon(Fanfiction, Readers head)
This is a reader-specific canon as the writer's equivalent is SpritCanon. It is what the reader thinks can happen based on the information given by the canon writing. This can be anything from assuming something due to a weirdly out-of-context sentence to accidentally realizing the ending to the series because of a series of foreshadowing events.
SoulCanon(Reader's heart, author's heart)
This is the bullshit that no one will ever agree with you on because there is no basis for it. It is what you believe and want to happen in your soul for one reason or another despite the narrative of the writing saying otherwise. Readers mostly have this form of canon but writers can sometimes do this too, making it the bi of the Canons. Unlike SpiritCanon, SoulCanon has no basis in the canon story itself. Think of it Teen Titans Go compared to Teen Titans, the characters, story, style, and feeling are all different despite sharing a similar name. Oftentimes, this is reserved for shipping characters that have never actually met.
CrotchCanon(every plausible medium)
This is what it sounds like. It is what you feel horny for whether the narrative allows it or not. There is no other category for it as it can fit into all the other Canon categories as needed. If SoulCanon is bi then CrotchCanon is pan as writers, readers, and non-readers will often take part in the smut fanfics. Smut writers will use this and even non-smut writers will partake in this occasionally as some studies(I pulled out of my ass because I heard a famous author say this once) say that a quarter of people with writer's block are stuck because they are stuck on a horny scene. It is shameful but I believe it is true since half of the books written during National Novel Writing Month, which also happens to take place during NNN, are smut.
What do you think of the different Canons? Is there more that you can think of? Do you have any of the following for a story that you can identify and categorize?