The title says it all! As for me, I have a few particular shortcuts in mind, for each category. But before I say which ones were the first ones for me, I will have to say what I consider to fit in my categories. For the intended one, I consider every shortcut that the ghosts do, or is very obviously intended(having boost panels there, ramps etc.) for example the ramp im Luigi’s circuit. The unintended one, mostly anything that isn’t “game breaking”. These include shortcuts like the Toad’s factor lake jump. And for the final one, I would say anything that “breaks the game engine”. What I mean by that, is something like the BCWii glitch. Now for my picks! For the intended one, I am pretty sure it was either the Wario goldmine left side, or the Maple tree way one. For the unintended one, I’m pretty sure my first one was the grumble volcano rock hop, or the Toad’s factory one. And for the final one, I would say It was the Grumble volcano lap skip. I am really interested in what we’re your first shortcuts, and if you want, you can say we’re you found out about them! For me I found out about almost all of them from a YouTuber called TWD98 who I still watch to this day.