Book Suggestion: What If?
During my undergraduate career, I took a course in fiction writing that left me with a textbook I highly recommend for any writer who finds value in utilizing prompts as writing practice.
Available on Amazon for about $35 used, What If? Writing Exercises for Fiction Writers (3rd Edition) is a great investment if you'd like a ton of writing exercises that focus on different important elements of creative writing, including beginnings, character development, voice, dialogue, plot, etc. The authors also guide you with pointers with each exercise that are very helpful and often result in an "Ah-hah" moment if its an element where you were previously stuck. The examples they provide are fantastic to help you refine your skill in areas where you may be lacking. Don't be too picky with this text; try all 115 exercises! You won't be disappointed.