Wallpaper sites that you can use for aliucord transparency theming.
https://wallhaven.cc/
https://wall.alphacoders.com/
https://www.hdwallpapers.net/
https://www.wallpaperfusion.com/
https://wallpaperaccess.com/
https://wallpapers.com/
https://wallpapersafari.com/
https://coolbackgrounds.io/
https://sys.re/pics/wallpapers/
https://wallpapercave.com/
https://www.positrondream.com/
https://skinbase.org/
https://getwalls.io/
http://www.wallpapersmania.com/
http://www.wpgallery.com/
https://thewallpapers.org/
https://www.socwall.com/
https://wallpapertip.com/
https://www.wallpaperflare.com/
https://hdqwalls.com/
https://www.desktopnexus.com/
https://wallpaperwaifu.com/
https://wallpaperstock.net/
https://wallpaperhub.app/
https://www.uhdpaper.com/
https://mega.nz/folder/QZwW1LLZ#WFjZoQNQm7LfyQzr_rUNIA/folder/MEZTVYDB
https://wallpapers.microsoft.design/
http://wallcoo.net/
https://vlad.studio/wallpapers/?sort=free&filter=all
http://www.ewallpapers.eu/
https://bingwallpaper.anerg.com/
http://simpledesktops.com/
https://www.dualmonitorbackgrounds.com/
http://wallpapers.net/
http://dl1.doostihaa.com/files/Wallpaper/
https://goo.gl/photos/HjY1hmo6p3jfFz8a7
Stock images:
https://www.everypixel.com/ (Search Engine)
https://png.is/tool/findstock
https://unsplash.com/
https://nohat.cc/
http://librestock.com/
https://www.freeimages.com/
https://www.pexels.com/
https://pixelmob.co/
https://www.reshot.com/
https://pixabay.com/
https://pngimg.com/
https://stocksnap.io/
http://creativity103.com/
http://photopin.com/
https://photos8.com/
https://storyset.com/
https://allthefreestock.com/
https://altphotos.com/
https://www.rawpixel.com/
https://barnimages.com/
http://imagebase.net/
http://gratisography.com/
https://skuawk.com/index.html
https://www.si.edu/OpenAccess
http://compfight.com/
https://burst.shopify.com/
https://negativespace.co/
https://picjumbo.com/
https://kaboompics.com/
https://2.flexiple.com/scale/multi-color-illustrations
http://freeillustrations.xyz/
https://www.behance.net/
https://undraw.co/
https://www.freepik.com/
https://www.dreamstime.com/free-photos
https://downloaders.beatsnoop.com/
https://all-free-download.com/free-photos/
https://www.desirefx.me/category/stock_images/
https://morguefile.com/photos
https://www.chamberofcommerce.org/findaphoto/
https://search.creativecommons.org/
http://gfxmountain.com/stock-photos/
https://www.goodfreephotos.com/