A seamless pattern of dark bricks. Maybe it's not very realistic, but it looks good in my opinion.
Source V. Hartikainen
Brushed aluminum, in a bright gray version. Lovely 2X as well.
Source Andre Schouten
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Some dark 45 degree angles creating a nice pattern. Huge.
Source Dark Sharp Edges
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
Prismatic Groovy Concentric Background 3
Source GDJ
This is a seamless pattern which is derived from a flower petal image.
Source Yamachem
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
An abstract web texture of a polished blue stone (or does it look more like ice).
Source V. Hartikainen
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
This is the remix of an OCAL clipart called "Art Nouveau ornament" uploaded by "microcosme".Thanks.This is a seamless pattern of an Art Nouveau ornament.
Source Yamachem
Bit of a strange name on this one, but still nice. Tiny gray square things.
Source Carlos Valdez
A series of 5 patterns. That’s what the P stands for, if you didn’t guess it.
Source Dima Shiper
Prismatic Floral Pattern 3 Variation 3 No Background
Source GDJ
Prismatic Triangular Background Design Mark II 5
Source GDJ
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
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