Pokemon Shiny Hunting Wikia

A Shiny Locked Pokémon cannot be shiny unless it is obtained from an event. These were introduced in Black and White. As a result, any Pokémon before those games can be shiny (barring most events).

The Pokémon in the following list cannot be encountered as shiny under any circumstances.

BW B2W2 XY ORAS SM USUM SwSh Legends: Arceus
Victini Reshiram Articuno Kyogre Tapu Koko Tapu Koko Keldeo Alolan Vulpix
Reshiram Zekrom Zapdos Groudon Tapu Lele Tapu Lele Type: Null Alolan Ninetails
Zekrom Moltres Rayquaza Tapu Bulu Tapu Bulu Silvally Uxie
Mewtwo Deoxys Tapu Fini Tapu Fini Cosmog Mespirit
Xerneas Cosmog Cosmog Cosmoem Azelf
Yveltal Cosmoem Cosmoem Poipole Dialga
Zygarde Solgaleo Solgaleo Naganadel Palkia
Lunala Lunala Zacian Heatran
Necrozma Necrozma Zamazenta Regigigas
Zygarde Zygarde Eternatus Cresselia
All Ultra Beasts All Totem Pokemon Kubfu Phione
Urshifu Manaphy
Glastrier Darkrai
Spectrier Shaymin
Calyrex Arceus
All Galarian Legendary Birds Tornadus

In ORAS, all Mirage Spot Pokémon, including Legendaries, can be shiny. In USUM, all Ultra Wormhole Pokémon, including Legendaries and Ultra Beasts, can be shiny. In addition, the Ash Cap Pikachu in USUM is set to be shiny locked, however, due to an oversight, it checks Pikachu's PID against the Player's TID and SID, instead of Ash's TID (170715) and SID, meaning that, unless the player has the same TID and SID, it can be shiny; it does not, however, have a shiny sprite, and will appear normal, with a shiny animation.

In SWSH, all Dynamax adventures pokemon can be shiny, including Legendaries and Ultra Beasts, these cannot be soft resetted and require a new adventure to be started to roll new odds. They also do not appear as shiny until the summary screen after the adventure has ended.