It's nothing particularly new to see cut content that didn't make it into the final version of Persona 5 or Persona 5 Royal. But this time a pretty special scene has surfaced, featuring all the adult Confidants in the game gathering together to celebrate. Be warned, this article and the featured video contain spoilers for the plot of Persona 5 Royal!
You can see the full scene below, which was cut from the final version of Persona 5 Royal. Note that the dialog in the scene has been fan translated from the native Japanese, but the scene itself shows all the adult Confidants gathering together in the Crossroads bar to celebrate the victory of Joker and the rest of the Phantom Thieves over the God of Control and Takuto Maruki's false reality.
Had the scene made the final version of Persona 5 Royal, it would've marked the first time plenty of these characters had crossed paths. Sojiro never met either Iwai or Yoshida over the course of the entire game for example, since Joker would always venture out into Tokyo to meet either Confidant, far away from Cafe LeBlanc.
The scene itself shows all the adult Confidants giving thanks to Joker and company, not long before Persona 5 Royal actually ends. They've all been gathered together by Sae Niijima and Sojiro Sakura, to give thanks for generally nurturing Joker over the past year. The event takes place on 4/20, and I'm just going to assume that's a massive coincidence and Atlus probably weren't aware of its connotations with meme culture at large.