Wallpapers:

• www.deviantart.com/electrolex/art/Foobar2000-v3-0-Plus-8K-Wallpaper
• www.deviantart.com/iprad/art/25-563925233
• www.deviantart.com/kalca/art/Foobar2000
• www.deviantart.com/seshasgaming/art/Gold-w11-959399171
• www.deviantart.com/sgt-meddle/art/foobar2000-Light-Dark-Minimalist-Wallpapers
• www.deviantart.com/tablesaltz/art/Foobar2000-Wallpaper

Dynamic Wallpaper:

www.reddit.com/r/foobar2000/comments/hf83m9/foobar_wallpaper_engine

Related Resources:

CUI &  DUI Themes List
Icons & Icon Sets