Here is a link to the Sherwin Williams Color Visualizer - https://www.sherwin-williams.com/visualizer#/active

You upload a photo of your room and then you can choose paint colors to try out. I suspect the other paint brands have a similar online tool, but this is the only one I am familiar with.

Maybe post a pic of the space here and explain why an accent wall. IMO accent walls need context not just some color out of the blue .