Deck ideas for unused cards

I have lots of decks, from good to new to silly to gimmicky.

But I still have a bunch of cards I'm not using. I want some ideas for decks that can use them. Format doesn't matter, other than not standard.

It doesn't need to be a complete checklist (though that would be awesome), but any idea to get the creative juices flowing. It can use cards that are already used, but it's prefer sticking to more of the unused ones.