the real gsc tiering

GSC Rankings

SS
Snorlax

S
Raikou
Zapdos

A
Exeggutor
Gengar
Cloyster
Skarmory
Tyranitar

B
Suicune
Nidoking
Machamp
Marowak
Vaporeon
Steelix
Jolteon
(Here and below could be labeled as "B-" if you want to do it that way, but there's nothing super huge separating these two groups. All of them are quite equal in usability and should just be all under one big "B" category.)
Heracross
Misdreavus
Umbreon
Miltank
Starmie
Forretress
Golem

C
Jynx
Rhydon
Charizard
Tentacruel
Quagsire

D
Blissey
Dragonite
Muk
Porygon2
Pilowswine

F
Espeon
Alakazam
Smeargle
Clefable
Houndoom
Tauros
Ursaring
Nidoqueen
Slowbro
Kangaskhan