Fan art
Isn't it horrible that Twitter doesn't have a tagging system that people used? You can try seaching #juhaku, but you can also put words like these in the search bar: 龍ジュダ (hakuju) or ジュダ龍 (juhaku) to find artist accounts. Without the text in parantheses of course. There are also many good Korean artists. You can also try Korean search words, like 백쥬 (Hakuju).

On Pixiv, the tags for this ship are 龍ジュダ and ジュダ龍. The Juhaku tag is larger, but the Hakuju tag is more active nowadays.

Find a lot of western art on Tumblr by searching Juhaku. Hakuju tag was often not used there. There is also reposted Japanese art to be found on there (hopefully they asked for permission). Find a lot of Juhaku-related Tumblr posts reblogged on here. There is also this Daily Juhaku Tumblr blog that has since gone inactive. You can find art on there as well as fic recs.

Some art and cosplay images can be found on Instagram with the tag juhaku.

There's a little of something on the good old deviantArt. Search Juhaku (a bit more here) or Hakuju (very little here).

If you are interested in buying items with fan art, there are some to be found on redbubble when it comes to western artists, and when it comes to Japanese artists. You need to use a proxy service if you want to buy from when outside of Japan.

For Chinese Juhaku, use the tag 裘龙 (Simplified) or 裘龍 (Traditional). You can switch them around like 龙裘 and 龍裘. For example, Juhaku on Lofter.