@vaporeon_ yes, in diamond/pearl/platinum (though the item you needed fur the event was never obtainable legitimately), in the brilliant diamond and shining pearl remakes (though the item you need was obtainable as a mystery gift that i think the window fur is by now long closed), and in legends: arceus, after you have caught every* other pokémon in the game

* there are two pokémon that are only obtainable if you have save data of other specific pokémon games on your switch, which, thankfully, are not required fur the arceus event to trigger