Three & four column layouts.

I am not including visual examples of a three- or four-column layout here because frankly, there just isn't real estate for that many columns once you add in a sidebar. They look horrible on mobile. Also, the theme filter for these options pulls in a crazy amount of themes that aren't three or four column. It's a common problem because theme designers tend to tag their themes with all the options, whether they truly satisfy the criteria or not.

Because themes must adjust dynamically to accommodate various screen sizes for mobile devices, I don't recommend any more than a two column layout for your website. Still, as in everything else here at WA, it's your business and your decision.