Yuu☆Yuu☆Hakusho: Eizou Hakusho - Opening Ending Encyclopedia

Quite a rare piece of content for an anime, this is not just intros and outros, but interspersed with character skits of them discussing various slice of life situations, giving a sort of "post story", and just a bit more time with each of the characters. I have to complement the voice actors here, because it really feels like they were putting themselves back into the shoes of everyone. I'm unsure the order they filmed these in, but it's arguably some of the best voice acting work in the series.

The isn't all that much to say about the intros and outros, but they are ... exactly what you would expect. If you haven't listened to them in a few months it's as good as it gets, but if you just completed the series I could see it being boring, and less of an exciting nostalgia trip.