It's not really a glitch but it's more or less a bug, but there's a spot in Pokestar Studios where you can use surf on the trees.
The Insta-win glitch ... or hack idk or if its not a glitch,mew glitch i guess , no, not mew under the truck
As many did, I also enjoyed MissingNo and the Mew Glitch. I missed the Mew event, I don't know if it came to my local Toys R Us but either way, it occurred about a year or two before I got into the franchise which was in 2000 and I doubt my mom would have taken me anyway (I was 13). I also found Glitch City and Cooltrainer Ditto pretty fun. In the second gen, the cloning glitch was the only one I'd discovered before all three of my games died and I exploited the hell out of that thing in Silver.