squirtle is because it is a water type and most people are rock or ground. Make sure you get different Pokemon though because its water attacks are not very effective on the first person in the elite 4
mudkip
It is either Torterra or Blastoise.It depends on what version of Pokemon you are talking about. If you mean out of every version, then Charizard would be the best starter Pokemon to have.
Use a Starter Kit! Starter Kits of the best way to do it! Try Google and Search Pokemon Starter Kit! There are 2 Versions a offline line version (more info on the site)
All of the starter Pokemon are the best
1. Torchic (starter)2. Taillow Here are two main Pokemon to win (or easiest)
Tepig
the best starter deck are squirtle sindoquil and turtwig
piplup
piplup is the best starter pokermon piplup is the best starter pokermon --------------------------- I chosed Turtwig grass type
Chimchar
It's really up to whatever you prefer, but cyndaquil is the easiest to beat the first few gym leaders with.
the best Pokemon to pick at the start is PIPLUP or CHIMCHAR