History GameBreaker / PokeMon

* Volcarona has always been a particularly polarizing 'mon, deemed the 'Matchup Moth' for its ability to either completely break a match wide open or flounder around helplessly, and while it has received changes that assisted it greatly in the past few generations, (Fairy-types to prey upon in Gen 6, Z-Moves to nuke with for Gen 7 only, Heavy-Duty Boots to ignore Stealth Rocks in Gen 8), ''nothing'' could have prepared players for the terror of a Volcarona that can use Terastalization. One would think that the returning Heatran would be a solid answer, as it has been for the past three generations, but Terastalization ruins that, as Volcarona can run Tera Ground or Tera Water to obliterate Heatran where it stands, while also slaughtering the similarly difficult Unaware Skeledirge. It could run Substitute for Sucker Punch, or even run Tera Ghost to blank Extreme Speed Dragonite. The average Choice Scarfers can't even reliably revenge kill it because they get outsped after Volcarona gets a Quiver Dance (which is very easy considering how many Pokémon Volcarona threatens now) it can essentially handpick its counterplay, similarly to Magearna, and as a result, in a very controversial move (many saw Zamazenta-Hero as a more pressing concern), Volcarona was banned from OU alongside Urshifu Rapid Strike. It would be unbanned after the release of the ''Indigo Disk'' DLC, however.

* The Psychic type in general isn't quite as overpowered as in generation 1, due to the addition of the Dark type and improvements to Bug and Ghost move pools. However, Alakazam is in some ways even more powerful, because you can purchase TMs for all of the elemental punches (Fire Punch, Ice Punch, Thunderpunch), and the physical/special split hadn't happened yet, so all of those punches run off its very high Special Attack stat, instead of its pathetic physical Attack. With STAB Psychic, Ice Punch, Thunderpunch, and Recover, a punching Alakazam can take on almost any foe, dealing at least neutral and usually super-effective damage, backed by very high stats. Trading it back to generation 1 (because the punches existed there, they just weren't available for purchase, so it's a legal trade) makes it nigh unstoppable.

* Last Respects is an ''insane'' move. For every fainted Pokémon you have, the power of Last Respects goes up by 50, up to a maximum of ''300 base power,'' and this isn't even taking STAB into account! On top of that, Houndstone, the premier user of the move, also has Sand Rush as an Ability, doubling its Speed in a sandstorm, ensuring it's going to sweep up the enemy team if it's the last Pokémon standing. A very common strategy with Houndstone is to bring five Pokémon to act as a suicide squad, with at least one Sandstorm setter, and then bring out Houndstone to destroy the enemy team. That strategy was so powerful, Houndstone received instant bans from competitive play. Upon Pokémon HOME's release, Basculegion, a new user of the move who had slightly better Attack [[note]]For the male, the female has a slightly lower Attack than Houndstone[[/note]] and Speed and a similar ability in Swift Swim was potentially able to do the same thing. As such, Last Respects was banned. [[note]]Due to Smogon policies, Houndstone was banned due to being the only user of Last Respects, but now that it was determined the move was the issue, Houndstone got unbanned.[[/note]] And even then, its power in Ubers as an easy to set up win condition is already giving it a suspect test in that tier as well.

* Playing the original monochrome games on a Platform/GameBoyColor is a game-breaker in that dark areas like caves suddenly becomes trivial to traverse. Likewise, hidden routes will suddenly become visible. This is largely due to how the Game Boy Color handles monochrome games made for it's predecessor and certain oversights in the choosing of the colors for it's 10 predefined palettes for those games did not account for games that relies on the monochrome screen to hide the hidden paths and/or mask the route.