H1h223
The Concept of Crossovers from the same series isn't new in Japan. Kamen rider did it, So Did Super Sentai. Precure also has one. The Event is called Precure All Stars. It's Debut is in 2008 with the Yes! Pretty Cure 5 GoGo! squad getting one.
Then in 2009 the very first All Stars movie titled Pretty Cure All Stars DX: Minna Tomodachi - Kiseki no Zen'in Daishuugou! was announced and screened in March of the same year, featuring the first four generations excluding the mid-season Cure for Fresh!. This format was carried onto Future All Star specials
Next format change would be a passing of the torch would happen in Happiness Charge Pretty Cure!, each season ends with a "passing the torch" scene where the main Cure from the completed season hands over to the lead Cure for the next season. This tradition is inspired by the Hand-Off Super Sentai tradition. Mahou Tsukai Pretty Cure! even had the lead Cure of the next season appear in its last episode. This tradition has continued in all seasons produced afterward.
Pretty Cure's 15th anniversary happened and with the series HUGtto! Pretty Cure had two crossover episodes (episodes 36 and 37). The series' special movie, HUGtto! Pretty Cure♡Futari wa Pretty Cure: All Stars Memories, was a crossover feature that included lines from all 55 existing main Cures. Starting with HUGtto!, the anniversary season's standalone movie was turned into an All Stars movie, similar to what was done with the movie for Hirogaru Sky! Pretty Cure to celebrate Pretty Cure's 20th anniversary in 2023.
Their are Even Precures deticated to All-Stars. Like Sakagami Ayumi as Cure Echo From
Pretty Cure All Stars New Stage: Mirai no Tomodachi