While it was already known that Pokémon would be a sponsor of the Rain City Showcase Basketball game, it turned out that at the event a special Pikachu promo was handed out (Pikachu from Paldean Fates with a Rain City Shpwcase stamp). This was not announced in advance to my knowledge and it’s currently unknown if there will be further distribution of this card or if it remains event exclusive. So if someone is a dedicated Paldean Fates Master Set collector… good luck.
Further photos of the event including (seemingly) exclusive shirts that were also available can be found on the Climate Pledge Arena Instagram account. If anyone has further information feel free to add it in the comments.