From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A free tileable background colored in off-white (antique white) color.
Source V. Hartikainen
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Seamless Prismatic Pythagorean Line Art Pattern No Background. A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
Prismatic Curved Diamond Pattern 6 No Background
Source GDJ
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
The image is a remix of "edo pattern-samekomon".I changed the color of dots from black to white and added BG in light-yellow.
Source Yamachem
Background Wall, Art Abstract, Star Well & CC0 texture.
Source Ractapopulous
Sort of like the back of a wooden board. Light, subtle, and stylish, just the way we like it!
Source Nikolalek
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
Basket Fibers, Basket Texture, Braid Background style CC0 texture.
Source 1A-Photoshop
More tactile goodness. This time in the form of some rough cloth.
Source Bartosz Kaszubowski
This one is amazing, truly original. Go use it!
Source Viahorizon
It has waves, so make sure you don’t get sea sickness.
Source CoolPatterns
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
Detailed but still subtle and quite original. Lovely gray shades.
Source Kim Ruddock
Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
The tile this fill pattern is based on can be had by using shift+alt+i on the rectangle.
Source Firkin