Sometimes there are two items from completely different ranges which suddenly go together.
My daughter got the Tim Holtz Fanciful Flight ™ butterfly when it came out- it's a versatile die as you can put both wings on or just the one to view from the side and you can just use the top wings to make a dragonfly. I had the Sizzix Heart Lock & Keys die and noticed that the keys were the same size as the butterfly body.
So I found some gold card for the lock, keys and outside of the wings and some softly pretty paper for the background of the card and of the wings (there are two wing-shaped holes hidden by the embossed panel - waste not, want not).
With two friends (who are partners) with birthdays only a couple of days apart and who both like Harry Potter (the winged key in the first book/film) - I made a pair of complementary cards. Different enough that they didn't get assembly-line cards, but linked.