Lovely pattern with splattered vintage speckles.
Source David Pomfret
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Prismatic 3D Isometric Tessellation Pattern 6
Source GDJ
More tactile goodness. This time in the form of some rough cloth.
Source Bartosz Kaszubowski
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
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
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
A cute x, if you need that sort of thing.
Source Juan Scrocchi
Super detailed 16×16 tile that forms a beautiful pattern of straws.
Source Pavel
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
More in the paper realm, this time with fibers.
Source Jorge Fuentes
It’s an egg, in the form of a pattern. This really is 2012.
Source Paul Phönixweiß
Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Love the style on this one, very fresh. Diagonal diamond pattern. Get it?
Source INS
Formed by distorting a JPG from PublicDomainPictures
Source Firkin
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
Same as gray sand but lighter. A sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
The edges of all the red objects line up either vertically or horizontally, but it doesn't appear so. Made from a square tile that can be got by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
There are many carbon patterns, but this one is tiny.
Source Designova