General synonyms:
* Imagination
* Originality
* Innovation
* Inventiveness
* Resourcefulness
* Ingenuity
* Vision
* Inspiration
* Artistic talent
* Artistic flair
* Conceptualization
* Conceptual thinking
* Thinking outside the box
* Problem-solving
* Brainstorming
More specific synonyms:
* For artistic creation: Artistic expression, artistic skill, artistry, craftsmanship
* For problem-solving: Innovation, ingenuity, resourcefulness, out-of-the-box thinking, problem-solving skills
* For business: Entrepreneurship, innovation, disruptive thinking, strategic thinking
* For writing: Imagination, storytelling, writing ability, literary talent
* For design: Aesthetic sense, visual creativity, design thinking
Informal synonyms:
* Bright ideas
* Thinking up new things
* Coming up with new stuff
* Out-of-the-box thinking
* Thinking different
The best synonym for "creativity" will depend on the specific context in which you are using it.