The Legendary Pokemon Registeel lacks official pre-evolutions, but a Pokemon enthusiast has created their own. Registeel originally appeared in the Generation 3 Pokemon games Ruby and Sapphire and has since appeared in various other Pokemon games.
In subsequent Pokemon games following Ruby and Sapphire, Registeel could only be obtained through trading. However, in some games, this legendary Steel-type has made a comeback as a native Pokemon. The most recent main series Pokemon games, Sword and Shield, introduced Registeel in the Crown Tundra DLC. While Registeel cannot be captured in Scarlet and Violet, there is a possibility that this could change in the upcoming DLC for the games.
Fans should not expect any pre-evolutions for Registeel in the Pokemon Scarlet and Violet DLC. Legendary Pokemon typically do not have pre-evolutions, although some fans have created their own designs. Reddit user cheez_it_boi979 recently drew their own pre-evolutions for Registeel, naming them Regitin and Regilead, which eventually evolve into Registeel. The user also provided Pokedex entries for each creature, stating that Regitin is only seven inches tall, Regilead is 2'11", and Registeel is 6'03".
While there are no official pre-evolutions for Registeel in the Pokemon video games, there are other "Regi" Pokemon that fans can catch and add to their team. Registeel debuted in the Generation 3 games alongside Regirock (Rock-type) and Regice (Ice-type). In the Generation 8 games, two more Regi Pokemon were introduced: Regieleki (Electric-type) and Regidrago (Dragon-type). There are still Pokemon types that do not have their own unique Regi Pokemon, but this may change in future Pokemon games.
Fans should not expect any new Regi Pokemon to be introduced in the upcoming Pokemon Scarlet and Violet DLC. Instead, the DLC might unveil paradox forms for the existing Regi Pokemon. However, this is highly unlikely considering that leaked information from The Teal Mask Pokedex does not mention any such Pokemon. It is possible that there might never be new Regi Pokemon, but if any are ever introduced in the future, it would most likely be in the Generation 10 Pokemon games.
As of now, the Generation 10 Pokemon games have not been officially announced. However, clues within Scarlet and Violet hint at a potential region based on Australia in these future games. Fans will likely have to wait for several years before any confirmation, so in the meantime, Pokemon enthusiasts can continue creating fan art and eagerly anticipate the release of the Scarlet and Violet DLC.