Non shiny blue Pokémon:
Squirtle
Wartortle
Blastoise
Sandslash Alolan Form
Nidoran♀
Nidorina
Nidoqueen
Ninetales Alolan Form
Oddish
Gloom
Golduck
Poliwag
Poliwhirl
Poliwrath
Tentacool
Tentacruel
Horsea
Seadra
Gyarados
Lapras
Vaporeon
Omanyte
Omastar
Articuno
Dratini
Dragonair
Totodile
Croconaw
Feraligatr
Chinchou
Lanturn
Marill
Azumarill
Wooper
Quagsire
Wobbuffet
Kingdra
Phanpy
Suicune
Mudkip
Marshtomp
Swampert
Surskit
Azurill
Sharpedo
Wailmer
Wailord
Swablu
Altaria
Whiscash
Castform Rainy Form
Chimecho
Wynaut
Spheal
Sealeo
Walrein
Clamperl
Huntail
Bagon
Salamence
Regice
Latios
Kyogre All forms
Piplup
Prinplup
Empoleon
Shinx
Luxio
Luxray
Cranidos
Rampardos
Shellos East Sea
Gastrodon East Sea
Riolu
Lucario
Finneon
Lumineon
Mantyke
Azelf
Phione
Manaphy
Oshawott
Dewott
Samurott
Panpour
Simipour
Woobat
Swoobat
Tympole
Palpitoad
Seismitoad
Sawk
Darmanitan Zen Mode
Tirtouga
Carracosta
Ducklett
Karrablast Deino
Zweilous
Hydreigon
Cobalion
Froakie
Frogadier
Greninja
Vivillon
Clauncher
Clawitzer
Amaura
Aurorus
Popplio
Brionne
Primarina
Wishiwashi
Toxapex
Minior
Komala
Cosmog
Cosmoem
Necrozma Dawn Wings
Sobble
Drizzile
Inteleon
Rookidee
Rookidee
Corvisquire
Cramorant
Grapploct
Alcremie
Eiscue
Arctozolt
Arctovish
Zacian-hero
Shiny blue:
Gen 1 Pokemon
Squirtle
Nidoran (M)
Nidorino
Nidoking
Vemomoth
Psyduck
Golduck
Poliwag
Poliwhirl
Tentacruel
Ponyta
Cloyster
Voltorb
Electrode
Horsea
Seadra
Starmie
Ditto
Porygon
Snorlax
Articuno
Mew
Gen 2 Pokemon
Spinarak
Chinchou
Lanturn
Politoed
Yanma
Unown
Gligar
Shuckle
Corsola
Mantine
Houndour
Houndoom
Porygon2
Miltank
Suicune
Gen 3 Pokemon
Sceptile
Ralts
Kirlia
Gardevoir
Surskit
Medicham
Electrike
Illumise
Gulpin
Swalot
Castform Rainy and Snowy
Shuppet
Banette
Snorunt
Relicanth
Regice
Gen 4 Pokemon
Piplup
Prinplup
Empoleon
Spiritomb
Gible
Gabite
Munchlax
Mantle
Gliscor
Porygon-Z
Gallade
Phione
Manaphy
Gen 5 Pokemon
Emboar
Oshawott
Dewott
Samurott
Simipour
Palpitoad
Sawk
Darmanitan Zen Mode
Tirtouga
Carracosta
Trubbish
Vanillish
Vanilluxe
Elgyem
Cryogonal
Pawniard
Bisharp
Braviary
Cobalion
Gen 6 Pokemon
Mega Slowbro
Mega Pinsir
Mega Houndoom
Mega Sceptile
Mega Banette
Froakie
Frogadier
Skrelp
Dragalge
Tyrunt
Tyrantrum
Sylveon
Carbink
Bergmite
Avalugg
Xerneas
Gen 7 Pokemon
Alolan Sandslash
Alolan Meowth
Alolan Persian
Popplio
Brionne
Oricorio Sensu Style
Rockruff
Lycanroc all forms
Wishiwashi School Form
Komala
Xurkitree
Necrozma all forms
Blacephalon
Gen 8 Pokemon
Sobble
Drizzile
Inteleon
Rolycoly
Carkol
Coalossal
Arrokuda
Clobbopus
Impidimp
Morgrem
Snom
Indeedee both forms
Zacian
Hope I helped!
Source: this and this
