Gold Version: The following Pokemon are not available in Pokemon Gold and have to be traded from Silver, Red, Blue or Yellow:

Bulbasaur, Ivysaur and Venusaur
Squirtle, Wartortle and Blastoise
Charmander, Charmeleon and Charizard
Kabuto and Kabutops
Omanyte and Omastar
Vulpix and Ninetales
Meowth and Persian
Phanpy and Donphan
Ledyba and Ledian
Skarmory
Delibird
Articuno
Zapdos
Moltres
Mewtwo
Mew

Silver Version: The following Pokemon are not available in Pokemon Silver and have to be traded from Gold, Red, Blue or Yellow:

Bulbasaur, Ivysaur and Venusaur
Squirtle, Wartortle and Blastoise
Charmander, Charmeleon and Charizard
Kabuto and Kabutops
Omanyte and Omastar
Mankey and Primeape
Growlithe and Arcanine
Teddiursa and Ursaring
Spinarak and Ariados
Gligar
Mantine
Articuno
Zapdos
Moltres
Mewtwo
Mew