>>53155956>Gen 1Depends on the generation. Venusaur has been pretty consistently decent since Day 1 thanks to decent bulk and Sleep Powder. Charizard was the best in Gens 6 and 7 due to its Megas. If Megas ever come back in the future, Blastoise will become the best one by virtue of Shell Smash.
>Gen 2Typhlosion was the best in early generations, as a Fire type with Electric moves to beat Water types was a pretty cool niche. But as the years went on it lost Special Thunderpunch and never really got anything added to its movepool as compensation, slowly languishing until it was just removed from the games. Hisuian Typhlosion having worse stats and and Abilities is just salt in the wound. Feraligatr was been the best one after it got its Hidden Ability, but it hasn't been in the games for a while.
>Gen 3Blaziken was just outright broken back when it got its Hidden Ability and had its Mega, but Swampert has always had consistently good performance since its debut.
>Gen 4Infernape and Empoleon have both always been decent, but haven't been in the games for a while. If they ever come back and Empoleon gets Roost it'll be the best one.
>Gen 5These were all colossal shitmons on release. Serperior obviously became the best one in ORAS when it got access to Contrary, but was removed from the series two games later and hasn't been back. Hisuian Samurott is looking to be pretty good, though, Ceaseless Edge is an incredibly good move and Sharpness drastically raises its damage output.
>Gen 6Greninja. Obviously.
>Gen 7Incelroar is one of the best Pokemon ever made in Doubles, but all three of them are just shit in Singles.
>Gen 8Cinderace is the best one. Rillaboom was also pretty good in Gen 8 but has been drastically nerfed coming into Gen 9.
>Gen 9Skeledirge is currently the best one, but it's possible that the starters could get some drastic Tera-related buff in the DLC and shake things up.