Incense activated during the event may lead to encounters with Legendary
Pokémon—if you're very lucky!
Wild Pokémon will appear more frequently 
Nearly every Pokemon in Pokemon Go will be available in the wild, except Mythical, Ultra Beasts, and others. Regionals will continue to be region-locked. No Costumed Pokémon will be found in the wild.
The following list is not complete but gives examples.
Mew,
Celebi, Jirachi, Mewtwo, Smeargle, Shedinja, Kecleon, Giratina, Zoroark,
Larvesta, Volcarona, Scatterbug, Spewpa, Vivillon, Zygarde, Mudbray,
Mudsdale, Cosmog, Cosmoem, Morpeko, Eternatus, Kubfu, Urshifu, Maushold,
Dudunsparce, Gimmighoul, and Gholdengo
The following Pokémon will appear in 2k eggs.
The following Pokémon will appear in raids.
Note: Buzzwole will appear in the Americas and Greenland. Pheromosa will appear in Europe, the Middle East, Africa, and India. Xurkitree will appear in Asia-Pacific. Celesteela will appear in the Southern Hemisphere. Kartana will appear in the Northern Hemisphere. Stakataka will appear in the Eastern Hemisphere. Blacephalon will appear in the Western Hemisphere.
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