the best starter for frlg is bulbasaur
The reason why I choose bulbasaur:
Bulbasaur is super effective against the first two gyms and good electric gym. Fourth gym is pretty much neutral because of it poison typing. Psychic gym..... bulbasaur will go down. For poison gym bulbasaur is meh. Bulbasaur will go down against the fire gym. Last gym is ground, so bulbasaur is great. The majority of lorelei Pokemon is water ( althought she is an ice elite four) but becareful with its ice Pokemon obviously. 2 of bruno onix will go boom because of bulbasaur. For agatha, not good for bulba. Lance is..... Better not use bulbasaur for this(you know why). Also it have sleep powder, and it will be SO USEFUL (if you face a bulbasaur that knows sleep powder youre gonna have bad day). That is the reason why I choose it.
Source: I'm a nuzlocker, also I watch so many youtube
Hope I helped!