Best starter from each region

Warning long post.

Kanto: Given my extensive experience with Yellow version, I’m inclined to say none of them but for a reason. That reason is that what their strengths happen to be, other Pokémon are simply better at a given role than they are. Take Bulbasaur for example. Grass creams Water, Ground and Rock while being solid Cut users and putting people to sleep. It does get a bit of a boost for Gen 6 onward due to Poison typing beating Fairy but for its primary strengths, it simply falls short. There are no Water/Ground types in Kanto, hence its biggest strength simply isn’t there. Ditto Water/Rock since it only exists on the Fossils and you don’t face them in Gen 1 or any remake for that matter afaik. That means that against the plethora of Water types in Gen 1, Electric is just as effective, if not more so due to Tentacool/Tentacruel being Water/Poison(hence resisting Grass) and Electric isn’t vulnerable to Ice. For putting people to sleep, Bulbasaur gets Sleep Powder way too late and honestly Spore on Paras/Parasect is a more reliable option(also makes a very good Cut user and is an underrated counter to Psychic types). Then you factor in its weaknesses(bad against Flying, weak to Psychic types) and you find Bulbasaur to just be at an unfortunate casualty of the regional Dex. Squirtle’s deficiency is that there are tons of good Water types in Gen 1 and Gyarados is the biggest culprit given you get Magikarp on Route 3. With a bit of grinding, you can have an end-game monster for Misty’s Gym battle. Other options include Starmie, Lapras, Cloyster and Vaporeon. As for Charmander, he gets a rough start with the Gyms and suffers from the fact that Fire types in general are just bad in Gen 1. They even had to give him Metal Claw just to have a chance against Brock for FRLG. Charmander’s lone saving grace is that in Yellow version he is able to take advantage of Charizard’s Flying typing with the Fly HM(in Red/Blue he’s no different than Ninetales for the most part). Finally, Pikachu would have a rough start with Brock but once you get past him, he’s not bad. Yet he can’t evolve so it’s beneficial to dump him in lieu of Magnemite at Rock Tunnel or holding off for Jolteon in Celadon City. If I must pick one… it’s Charmander but by default and it’s only because he has useful utility with HM’s(and I generally don’t use him in lieu of Ninetales).

Johto: All three are pretty good but I’m going with Totodile on this one. Was my pick in Z-A and he’s solid in Johto.

Hoenn: Mudkip… the fact he can solo the game is enough

Sinnoh: Chimchar. Was torn here but I’ll give the edge to the fast Monkey and the fact I prefer Barry with Piplup.

Unova: I really love Snivy’s design but if I’m being truly honest, it’s Oshawott by a mile.

XY: Fennekin by default, especially if I play as Serena.

Sun/Moon: Litten for me… there’s a reason this Cat is a competitive monster when it hits Incinerorar and although I do like Popplio’s Water/Fairy, Alolan Ninetales exists.

Sword/Shield: Grookey. Got to bang those Drums.

Paldea: Fuecoco. Was my starter and I see no reason to change it.

I'm going to give answers because I don't like the meta conversations going on everywhere.

Bulbasaur

Cyndaquil

I can't decide between the Hoenn starters, but for constistency I'll give it to Treecko

Piplup (This one was close)

Oshawott (it would be my favorite starter if Samurott stayed on 2 legs and the line had better stats)

Froakie (My favorite starter evo line, each member is perfect in their own way)

Rowlet (second best starter line ever IMO, but just not one of my favorites)

Scorbunny (If only Cinderace was less human)

Sprigatito (Quaxly is one of my favorites, but the evolutions underwhelmed me a little, though by no means are they bad)

Yeah, I have things to get off my chest when it comes to Kanto and specifically Generation 1. In Generation 3(FRLG), the starters are significantly better, although I tend to hold the same thought process on Bulbasaur given that Water/Ground isn't in the regional Dex and Water/Rock that is on the Fossils is not faced(afaik) at all as well. You do get Sludge Bomb in Rocket Game corner to give it a decent STAB move but Poison has virtually no viability in Kanto because there's no Fairy types in Generation 3(Let's GO is a different story… where having it is actually ok given Fairy is added to Mr.Mime, Clefairy and Jigglypuff).

Squirtle is actually a solid option given Gyarados is weaker in Generations 2&3 due to the Special split so unless you prefer to wait until much later in the game for your Water type, Squirtle makes a solid starter and especially with Bite being a Dark Type move(hence wrecks Misty's Starmie). Charmander is also a solid pick because he's stronger than his Generation 1 counterpart. His Special Attack is 24 points higher(85 → 109) and he gets Flamethrower earlier as a Charmander(level 30 compared to 38, get it at 34 with Charmeleon that was at level 42(or level 46 as Charizard) in Gen 1, hence the wait is not as penalizing) along with Flying STAB(Wing Attack/Aerial Ace or Fly HM that he can actually learn compared to Red/Blue where he cannot get anything for Flying STAB… Yellow just permits Fly). In addition, Fire alternatives are "weaker" with Ninetales having her Special Attack neutered from 100 → 81 and Growlithe is still a royal bleeping pain because it doesn't learn Flamethrower until level 49 in Generation 3(so short of getting Flamethrower TM from Rocket Game corner, it's a LONG wait).

Hence if I was factoring Generation 3 or FRLG, I'd pick Squirtle, Charmander, Bulbasaur in that order.