looks viability rankings (formes excluded for now)

NOTE: will be updated, feel free to pm user yellow skarmory on pokemon showdown for any suggested changes.

Overview:

S rank: These pokemon look super fabulous.
A rank: These pokemon look classy.
B rank: These pokemon look good.
C rank: These pokemon look average.
D rank: These pokemon look bad.
E rank: These pokemon look garbage.

Sorted by dex number.

S rank:
S+:
S:
S-:

A rank:
A+:
A: Articuno
A-: Blastoise, Nidoking, Arcanine, Starmie

B rank:
B+: Charizard, Nidoqueen, Machamp, Rapidash, Gengar, Gyarados, Dragonair, Feraligatr, Crobat
B: Pidgeot, Pikachu, Clefairy, Ninetales, Jigglypuff, Vileplume, Electrode, Lapras, Aerodactyl, Meganium, Ampharos, Jumpluff, Scizor, Heracross
B-: Ivysaur, Beedrill, Rattata, Ekans, Vulpix, Growlithe, Alakazam, Ponyta, Voltorb, Hitmonlee, Chansey, Scyther, Jolteon, Flareon, Zapdos, Moltres, Dratini, Mewtwo, Mew, Typhlosion, Totodile, Marill, Azumarill, Hoppip, Espeon, Umbreon, Dunsparce, Steelix

C rank:
C+: Venusaur, Butterfree, Raichu, Clefable, Venonat, Persian, Golduck, Poliwag, Poliwrath, Victreebel, Tentacruel, Dodrio, Dewgong, Gastly, Hypno, Kangaskhan, Seaking, Eevee, Vaporeon, Kabutops, Bayleef, Cyndaquil, Furret, Ledian, Ariados, Lanturn, Cleffa, Igglybuff, Xatu, Mareep, Flaaffy, Sudowoodo, Politoed, Yanma, Quagsire, Murkrow, Slowking, Misdreavus, Girafarig, Snubbull
C: Bulbasaur, Squirtle, Fearow, Arbok, Sandshrew, Sandslash, Zubat, Oddish, Psyduck, Primeape, Poliwhirl, Abra, Weepinbell, Farfetch'd, Shellder, Haunter, Exeggutor, Hitmonchan, Staryu, Mr. Mime, Magmar, Tauros, Magikarp, Porygon, Omastar, Croconaw, Chinchou, Pichu, Bellossom, Skiploom, Aipom, Qwilfish
C-: Charmeleon, Pidgey, Pidgeotto, Raticate, Nidoran-F, Nidorina, Nidoran-M, Nidorino, Parasect, Venomoth, Dugtrio, Meowth, Mankey, Kadabra, Machop, Tentacool, Slowpoke, Slowbro, Magneton, Doduo, Seel, Cloyster, Krabby, Kingler, Marowak, Rhydon, Horsea, Jynx, Pinsir, Ditto, Omanyte, Dragonite, Chikorita, Quilava, Noctowl, Spinarak, Togepi, Togetic, Natu, Sunkern, Unown, Wobbuffet, Gligar, Granbull, Shuckle

D rank:
D+: Charmander, Spearow, Wigglytuff, Golbat, Gloom, Diglett, Machoke, Bellsprout, Geodude, Golem, Onix, Drowzee, Exeggcute, Cubone, Lickitung, Weezing, Rhyhorn, Seadra, Goldeen, Kabuto, Snorlax, Sentret, Hoothoot, Ledyba, Sunflora, Wooper, Pineco, Forretress
D: Wartortle, Caterpie, Weedle, Paras, Magnemite, Koffing, Tangela
D-: Metapod, Kakuna, Graveler

E rank:
E: Grimer, Muk

Current discussion (feel free to suggest stuff):
Gengar from B+ ---> A+