If you want to express the idea of being unique in a verb form, you could use words like:
* Distinguish - to be different from others
* Stand out - to be noticeable or different
* Differ - to be unlike something else
* Individualize - to make something unique
For example, instead of saying "The painting is unique," you could say:
* "The painting distinguishes itself from all others."
* "The painting stands out from the rest."
* "The painting differs significantly from other works."
* "The painter individualized the painting with distinct brushstrokes."