Pokemon Scarlet and Violet's most recent trailer has some very big Easter eggs that hint at ties to Pokemon Silver and Gold. Earlier today, The Pokemon Company released new information about Pokemon Scarlet and Violet, the new Pokemon games due out this fall. Although the new games are set in the Paldea region, a brand new region based on Spain and Portugal, players noticed several big hints that the games will also celebrate Pokemon Gold and Silver. A video released during today's Pokemon Presents used the New Bark Town theme song while introducing players to the Paldean version of Wooper, a Pokemon first seen in the Johto region. Additionally, gameplay footage revealed that the symbol used when a Pokemon Terastallizes – a new mechanic in which a Pokemon takes on a crystalline appearance – strongly resembles the crystal on Suicune's head.
Several Pokemon games have featured callbacks and ties to the original Pokemon Red and Blue games, but there have been limited reference to the Johto region. Most notably, Malie City in the Alola region was inspired by Johto architecture. A handful of Johto have also gotten regional forms – Corsola received a regional form (and a more tragic origin) in Pokemon Sword and Shield, while Sneasel, Qwilfish, and Typhlosion all received new forms in Pokemon Legends: Arceus.
One strong theory is that Terastallization is tied somehow to Suicune, or that the Legendary Pokemon has a new regional form in Pokemon Scarlet and Violet similar to how the Legendary Birds of the Kanto region had new forms in Pokemon Sword and Shield. Suicune and the other Legendary Beasts are popular Pokemon but they haven't been featured other than post-game content since the release of Pokemon HeartGold and SoulSilver over a decade ago.
Since Pokemon Scarlet and Violet seems to have a theme involving the past and future and the Johto region is most connected to the traditions of the past, we'll have to keep an eye out to see whether there are any other Johto connections.
Pokemon Scarlet and Violet will be released on November 18th.