CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
Your eyes can trip a bit from looking at this – use it wisely.
Source Michal Chovanec
Here's a tile-able wood background image for use in web design.
Source V. Hartikainen
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
Number 2 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
A free seamless background texture that looks like a brown stone wall.
Source V. Hartikainen
Pixel by pixel, sharp and clean. Very light pattern with clear lines.
Source M.Ashok
A seamless texture of worn out "cardboard".
Source V. Hartikainen
Number 4 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
This seamless light brown background texture resembles a wallpaper with vertical stripes. One way to use it is as a tiled background on web sites.
Source V. Hartikainen
Prismatic Snowflakes Pattern 3 No Background
Source GDJ
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
That’s what it is, a dark dot. Or sort of carbon looking.
Source Tsvetelin Nikolov
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
You were craving more leather, so I whipped this up by scanning a leather jacket.
Source Atle Mo
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen