We love to write, otherwise we'd never come up with these wonderful worlds and characters. We like the thrill of telling stories. But eventually, the story comes to an end and you need something new to work on.
In my case, I've finished, edited and formatted my three additional books in my series. They are just waiting for my cover artist to finish. (Can't ask a pre-vet student to drop everything for mom... I really want my free veterinarian lol). So in the mean time, I need to scratch that itch of writing. Here are a few ideas of how to keep your mind going.
1) Think of side stories, prequels and sequels to your work. What happened before your heroes changed the world? What brought them to that point.
2) Maybe expand on the backgrounds of some of your characters. This may fall into side stories, but as you wait for something to move on your "finished" story, you might find something that will add flavor to your story.
3) Maybe pick up an entirely new story line. I've been working on a story with "end of the world" sorta vibes, based in my lovely childhood home. It will probably go no where, but it gives me a creative outlet.
4)This also works for roleplaying games. Maybe you are a pause for your campaign because of real life, (darn that). Maybe fleshing out places, people or even plots will help you make an even more vibrant campaign.
Happy writing.