Here's a subtle marble-like background for use on websites.
Source V. Hartikainen
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
I love these crisp, tiny, super subtle patterns.
Source Badhon Ebrahim
Background formed from the original with an emboss effect
Source GDJ
An abstract Background pattern of purple twisty patterns.
Source TikiGiki
Prismatic Hexagonalist Pattern No Background
Source GDJ
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
A seamless gray background texture suitable for use on websites. To me, it has the look of stone. Feel free to modify it to meet your needs (by making it a bit lighter or darker, for example).
Source V. Hartikainen
This is the remix of "Strawberry Pattern Background" uploaded by "GDJ". Thanks. I realigned strawberries so as to get seamless and changed the BG color.
Source Yamachem
Alternative colour scheme for the original floral pattern.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
A very dark asfalt pattern based off of a photo taken with my iPhone.
Source Atle Mo
Formed by distorting an image on Pixabay that was uploaded by gustavorezende. To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Groovy Concentric Background
Source GDJ
Abstract Tiled Background Extended 10
Source GDJ
Prismatic Abstract Geometric Background derived from an image on Pixabay.
Source GDJ
Three shades of gray makes this pattern look like a small carbon fiber surface. Great readability even for small fonts.
Source Atle Mo
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin