It's hard to find a decent wallpaper for a landscape-portrait-landscape 3 monitor setup, but I think this will do the trick (Software Dev Battlestation) : r/battlestations
Rotate Screen in Windows 10 – How to Flip Your Monitor Orientation 90 Degrees
Landscape, nature, portrait display, pine trees, lake, mountains, forest, HD phone wallpaper | Peakpx
Change screen orientation - Microsoft Support
Essentials Lightroom Presets | HXE Presets
Dual monitor setup at work. One portrait and one landscape, made possible by swing arm desk mount, a… | Wallpaper repair, Dual monitor setup, Computer wallpaper hd
Screen Orientation - Change in Windows 8 | Windows 8 Help Forums