Colored maple leaves scattered on a surface. This is tileable, so it can be used as a background or wallpaper.
Source Eady
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
From a drawing in 'Handbook of the excursions proposed to be made by the Lincoln Diocesan Architectural Society, on the 27th and 28th of May, 1857', Edward Trollope, 1857.
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Colour version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male