Images that gets used for my custom backgrounds in tetr.io, which you should check the game out. Used to host them on Discord, but that was until the school network didn't allow images from Discord to show. So it's now hosted on GitHub. Eveything here is under 8MB and in .PNG format.
I do not own the backgrounds used except for one, all rights goes to their respective owners.
UPDATE - July 8th, 2022
This repo now also host songs for my website, not just background images for tetr.io anymore. Though bear in mind that not many songs will be added here, so it's still for tetr.io.