Ball pillows feel whimsical and charming.
They add visual interest and soften the lines of more structured furnishings.
And with so many fabric/color options, they are an easy way to bring a little color or contrast to a seat!
Here are a few sources:
Chairish – Ball Pillow, Citron
Sarah Sherman Samuel – Bouclé Ball Pillow
CB2 – Terre Olive Green Velvet Sphere Pillow