Remember when LEGO tried to emulate Nintendo’s amiibo™ figures? Ah yes, LEGO Dimensions. For some reason I have four. I must have purchased them at deep discount to harvest them for parts, but they’ve been gathering dust on a shelf since 2016. They’re probably the oldest unbuilt sets in my collection[1].
[1] Not strictly the oldest unbuilt sets, but the ones I’ve held the longest.