Bellow you'll find various sources to some of the best wallpaper websites around the net, if you have source not listed here, please post and it'll be added in ASAP.
Also, some wallpaper websites may display wallpapers that are not SFW. Use your own discretion on when or when not to be browsing wallpaper websites. We cannot guarantee that the site won't display inappropriate content. View at your own risk!
High-Resolution Wallpaper Websites
Wallpapers for Dual Monitors
Special thanks too: Krunk_Kracker, tr8rjohnk, Miki & JacKz5o. +