This addon adds additional 90 artworks for the simple viewport addon. 

This addon will not work without the simple viewport addon:

https://www.curseforge.com/wow/addons/simple-viewport

With simple viewport you can shrink the rendered world to get more space for raid groups, chats or other addons.

You can also can change the colour of the border and add artworks for all sides. Artwork can be stretch, recolour, clamp to the worldframe or add a fade out effect.

Most of the artworks are created by SunnArt (see links below) and are under GNU or Public domain.

Source:

https://www.curseforge.com/wow/addons/sunn-viewport-art
https://www.curseforge.com/wow/addons/sunn-viewport-art-pack-1
https://www.curseforge.com/wow/addons/sunn-viewport-art-pack-2
https://www.curseforge.com/wow/addons/sunn-viewport-art-pack-3
https://www.curseforge.com/wow/addons/sunn-viewport-art-pack-4
https://www.curseforge.com/wow/addons/sunn-viewport-art-pack-5
https://www.curseforge.com/wow/addons/sunn-viewport-art-pack-6
https://www.curseforge.com/wow/addons/sunn-viewport-art-pack-7
https://www.curseforge.com/wow/addons/sunn-viewport-art-pack-8
https://www.curseforge.com/wow/addons/sunn-viewport-art-pack-9
https://www.curseforge.com/wow/addons/sunn-viewport-art-pack-10
https://www.curseforge.com/wow/addons/sunn-viewport-art-pack-11

and some edit versions.