Seamless Green Tile Background
Source V. Hartikainen
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
You may use it as is, or modify it as you like.
Source V. Hartikainen
f you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Inspired by a pattern found in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
This texture looks like old leather. It should look great as a background on web pages.
Source V. Hartikainen
This is a remix of "blue wave-seigaiha".I hope this subtle color version of Seigaiha would be suitable for background .
Source Yamachem
Not the most creative name, but it’s a good all-purpose light background.
Source Dmitry
I scanned a paper coffee cup. You know, in case you need it.
Source Atle Mo
This one needs to be used in small areas; you can see it repeat.
Source Luca