I got to thinking about this the other day after I was playing Silver and my Togepi used Razor Wind via Metronome. Crystal was my first Pokemon game which I've played on and off since 2001, but I realised I'd never seen the animation for Razor Wind in any of the Gen II games, largely due to the fact that no Pokemon learns it naturally; it can only be obtained by trading a Pokemon which learned it via TM in RGBY. There are a few other moves like this, such as Submission, Pay Day, Horn Drill, and Fissure (all moves which were learnable by TM in Gen I, but which few Pokemon learn naturally in later gens). Aeroblast and Sacred Fire are also elusive in Crystal, as while Ho-oh and Lugia can be caught, both come at too high a level to know them.
So which moves are notably hard to find in certain games and generations? To give another example, Nightmare is completely unobtainable in Ruby and Sapphire - not only does no Pokemon learn it, but it can't even be used via Metronome since no Pokemon in those games learns that either. What are some other notable examples you can think of? Moves like Doom Desire, Psycho Boost, and Hyperspace Hole/Fury don't really count since they're mostly event-exclusive: I'm thinking more of commonplace moves that simply aren't seen very often due to poor distribution.
(&& please, no Gen VIII talk)
So which moves are notably hard to find in certain games and generations? To give another example, Nightmare is completely unobtainable in Ruby and Sapphire - not only does no Pokemon learn it, but it can't even be used via Metronome since no Pokemon in those games learns that either. What are some other notable examples you can think of? Moves like Doom Desire, Psycho Boost, and Hyperspace Hole/Fury don't really count since they're mostly event-exclusive: I'm thinking more of commonplace moves that simply aren't seen very often due to poor distribution.
(&& please, no Gen VIII talk)