Getting into a different environment, especially one you don't normally go to (do so safely, though!). Leave the screens behind and take a notebook, a good pen, and maybe a camera (an actual one, so you're not distracted). People watch, nature watch, traffic watch - whatever. Write notes, or your "What if..." questions, no matter how outlandish or mundane.

Change formats. You don't have to be good at it, just do something different. A poem, a different genre, find weird writing prompts online - and their strange responses!

Re-arrange your writing area, refresh it, make it new again.

Collaborate with a friend.

Do some creative critical thinking exercises - those questions with no correct answer, sometimes known as "thunks".

Create some mad libs (remember those?). Get friends and family to help.

Rediscover a child's wonder and how they see the world - the good and the scary.

Try to view humans from the perspective of other species of Earth.

Play some (or get your kids to talk to you about) story-driven games.

Do something creative but entirely different - even if you're terrible at it. Painting, pottery, sewing, cooking, jigsaw puzzles, etc.