Main series
Rose Tower first appeared in Sword and Shield: The Darkest Day!, where Ash was invited there for a meal there with Rose. Rose offered to mentor Ash, but he refused the offer, preferring to grow stronger while traveling the world himself. After spending a night at the tower, Ash left it the next day to reunite with Goh.
Pokémon: Twilight Wings
Rose Tower first appeared in Assistant, where Oleana was seen starting a day of work there while Rose was away for the day.
In Moonlight, Leon visited Rose at the tower to receive John's letter from him.
Pokémon Adventures
Rose Tower debuted in Crackle!! Practice Battle. Rose was seen receiving a phone call from Leon there, regarding the endorsement he was planning to give to Henry and Casey.
In PASS25, after learning of the Darkest Day that Rose was planning to unleash, Henry, Casey, Hop, Bede, Marnie, and most of the Galar League Gym Leaders entered Rose Tower to stop the chairman. Oleana challenged the Gym Leaders at the tower's lobby, while the others took the elevator to the top floor. Instead of Rose, however, all they found there was a giant screen, through which Rose spoke to them from Hammerlocke Stadium's Energy Plant. He had planned to wait until the Champion Cup would give him all of Galar's attention to start the Darkest Day, but due to the circumstances having changed, he announced he would start it immediately. As such, everyone then headed for Hammerlocke to stop Rose.
In PASS27, Macro Cosmos was seen observing the progress of the Darkest Day from Rose Tower, including the fact that Eternatus wasn't producing Galar particles at an expected pace yet, which Oleana relayed to Rose.
In PASS30, following Eternatus's disappearance, along with Henry, the Rusted Sword, and the Rusted Shield, Oleana gave Casey access to Macro Cosmos's supercomputer at Rose Tower so that she could figure out where they were now. Since she knew that the artifacts had been covered in Eternatus's poison, she used the National Pokédex database to search signs for a matching poison around the region, quickly figuring out that artifacts had wound up at the Isle of Armor and the Crown Tundra.