Changes whole character of room. Sofas and side chairs. No patterns here. Any solid color is considered neutral. It can be purple as long as it is not a pattern.
Textured patterns are fine.
Just not a variation in colors. Doing this will help your furniture endure the test of time. Pillows, small upholstered ottomans and drapery and area rugs. Which shouldn't be a problem if you began with solid colors to start with. Use any pattern you want or you can use solids in contrasting colors here.