Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Prismatic Geometric Tessellation Pattern 3 No Background
Source GDJ
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
You know I’m a sucker for these. Well-crafted paper pattern.
Source Mihaela Hinayon
It’s an egg, in the form of a pattern. This really is 2012.
Source Paul Phönixweiß
Tweed is back in style – you heard it here first. Also, the @2X version here is great!
Source Simon Leo
Number five from the same submitter, makes my job easy.
Source Dima Shiper
This is sort of fresh, but still feels a bit old school.
Source Martuchox
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Retro Circles Background 5 No Black
Source GDJ
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
This pattern comes in orange, and it looks as if it is "made of glass".
Source V. Hartikainen
A seamless textured paper for backgrounds. Colored in pale orange hues.
Source V. Hartikainen
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
A seamless paper background colored in pale yellow.
Source V. Hartikainen
Free tiled background with colorful stripes and white splatter.
Source V. Hartikainen