What species will benefit most from humanity's having been here?
Assuming that as a species, we do ourselves in, not through war but through environmental neglect and overpopulation, what species will benefit most from the effect we have had on the planet during our brief time at the top of the food chain?
I am writing a short story about an alien world where the inhabitants hold a predecessor species in high respect for all the treasures left behind before they disappeared long before the current sentient age. At the end of the story, I want the reveal to be that the planet is Earth and humanity is the predecessor species whose garbage and relics have helped the current race thrive.
I've considered rats because they already thrive on what we discard, and dogs because I would love to see a more noble species take the throne after us. But I am sure that there are other candidate species which might lead the story into wonderful new realms.
My criteria for "benefits most" is based on how much what we would leave behind might shorten the species's evolutionary journey to sentience.
On thinking about the other answers, I'm not sure this is possible without a little "something extra"... If humans sudde …