Background pattern 117 #524
Noise CC 0A seamless pattern drawn originally in Paint.net by distorting a slice of background pattern 116 and copying the resulting triangle numerous times.
Source Firkin
More Textures
Black And White Floral Pattern Background Inverse #196
Dark CC 0Black And White Floral Pattern Background Inverse
Source GDJ
Merely Cubed #589
Grid CC BY-SA 3.0Tiny, tiny 3D cubes. Reminds me of the good old pattern from k10k.
Source Etienne Rallion
Subtle Freckles #89
Light CC BY-SA 3.0This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
Decorative divider 192 #2503
Dark CC 0From a drawing in 'Worsborough; its historical associations and rural attractions', Joseph Wilkinson, 1879.
Source Firkin
Olive Green Web Background Image #1335
Green CC BY-SA 3.0Seamless Olive Green Web Background Image
Source V. Hartikainen
Polaroid@2X #188
Wall CC BY-SA 3.0Smooth Polaroid pattern with a light blue tint.
Source Daniel Beaton
Background pattern 215 (colour 4) #2368
Green CC 0A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Zig-zag pattern 2 #2417
Grid CC 0A seamless pattern based on a rectangular tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
One in a Million #1346
Gray CC BY-SA 3.0Nicely executed tiling for an interesting pattern.
Source Ignasi Àvila Padró
Project Papper@2X #120
Paper CC BY-SA 3.0Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
Tileable Off-white Background #1191
Concrete CC BY-SA 3.0A free tileable background colored in off-white (antique white) color.
Source V. Hartikainen
Tessellation 15 #2223
Dark CC 0The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Prismatic Hypnotic Pattern No Background@2X #572
Noise CC 0Prismatic Hypnotic Pattern No Background
Source GDJ
Prismatic Abstract Geometric Background 4 No Black@2X@2X #444
Dark CC 0Prismatic Abstract Geometric Background 4
Source GDJ
Dark Stripes #39
Dark CC BY-SA 3.0Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
Dark Brick Pattern #1032
Stone CC BY-SA 3.0A seamless pattern of dark bricks. Maybe it's not very realistic, but it looks good in my opinion.
Source V. Hartikainen
White Well & Star #1700
Wall CC 0Background Wall, Art Abstract, Star Well & CC0 texture.
Source Ractapopulous
P5@2X #1114
Light CC BY-SA 3.0Number five from the same submitter, makes my job easy.
Source Dima Shiper
Background pattern 234 #2259
Brown CC 0Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Broken Noise@2X #365
Dark CC BY-SA 3.0Beautiful dark noise pattern with some dust and grunge.
Source Vincent Klaiber
Aged Grid Paper Background #1072
Paper CC BY-SA 3.0A seamless web background with texture of aged grid paper.
Source V. Hartikainen