A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Here's an yet another seamless note paper texture for use as a background on websites.
Source V. Hartikainen
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A repeating background with wood/straw like texture.
Source V. Hartikainen
Some dark 45 degree angles creating a nice pattern. Huge.
Source Dark Sharp Edges
Original seamless pattern with an Inkscape filter.
Source Firkin
On a large canvas you can see it tiling, but used on smaller areas, it’s beautiful.
Source Paul Phönixweiß