In my opinion it is the pillow in the back (striped) that is blah. I like the textured pillows. How about another pillow in cream or an accent color to go with the textured pillow?

Start by selecting a color that goes well with the rest of the furniture and design of the room. Then select a couple of fabrics with that color shown minimally throughout. The fabrics should coordinate, but don't have to be identical. Graphic patterns of black/white and gray go with anything to layer as well.

The way it works is that the cover you're buying will fit a 20" x 20" insert. So they give you the size of the insert, not the cover, per se.

I think most of us answered defining “best” as plenty of choices and/or creative alternative choices. I like options for my personal look. OP had already gone to stores with specific styles.