Seamless tile drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Tiny, tiny 3D cubes. Reminds me of the good old pattern from k10k.
Source Etienne Rallion
Prismatic Rounded Squares Grid 4 No Background
Source GDJ
Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian
A new take on the black linen pattern. Softer this time.
Source Atle Mo
This light yellow background pattern consists of an irregular pattern of spots. Here's a light background pattern with yellowish tint.
Source V. Hartikainen
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
Dark, crisp and subtle. Tiny black lines on top of some noise.
Source Wilmotte Bastien
The image a seamless pattern derived from a weed which I can't identify.The original weed image is from here:https://jp.pinterest.com/pin/500744052301423641/
Source Yamachem
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
From a drawing in 'Kingsdene', Maria Fetherstonehaugh, 1878.
Source Firkin
Sharp pixel pattern, just like the good old days.
Source Paridhi
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Free tiled background with colorful stripes and white splatter.
Source V. Hartikainen
A dark metallic background with a pattern of stamped dots. Here's a dark "metallic" background pattern for you.
Source V. Hartikainen
White little knobs, coming in at 10x10px. Sweet!
Source Amos