I have also added backgrounds I have made at the top of this and add attributions to where I got other backgrounds from.
These are backgrounds I have created myself either for a purpose or just for the interest of how it was created.
This was made by making the code for jQuery fill the page and then use a pygments lexer to highlight the code.
A smaller version for smaller screens can be found here.
These are the backgrounds that are featured as my background in my YouTube videos.
This is currently my favourite as it is so clean and has a very happy feel to it. Icons site nicely on it and it is very clear being 1920x1080. I found this in a Google Image search but this is the origin
You will find I like material design and I used to try and design a lot of my projects to the specifications, this is obviously quite time-consuming so I settle for backgrounds, colours and icons.
This was also found by Google Image search but originated here
I really liked the colours in this background. Monitors that render colour well makes this image look amazing. Unfortunately, I don't remember where this image came from and a reverse image search is not providing hints by giving me 30 different results at the same resolution.
This image is a representation of some data collected by the LHC. I loved the idea and all the colours of this and the black backing was a bonus. This image was actually an icon for the video "Heavy Ion collision event display" on YouTube.