I put new stuff on https://megumin.love recently.
Now with flavors of other characters because I got bored so I killed some time by coding and procuring assets.
To activate, check the sidebar (megumin image) and scroll down to the the bottom of the background selection (you can scroll, even if there's no scrollbar) and check the last 3 entries.
Enjoy. (The megumin one is standard, just provided for completeness sake)
Welcome to your niu world ! We are a cute and loving international community Ｏ(≧▽≦)Ｏ !