Just wanted to share this youtube video I thought was pretty funny. It's not officially a glitch but it shows what happens if you don't get your starter Pokémon and use the 'walk through walls' cheat. It's pretty entertaining.
Here is my own version of the Mew glitch in Pokémon Yellow (ROM). I know it has been described but I want to put the video I did to show others that this really works and for those who haven't seen it.