The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
Background Wall, Art Abstract, white Well & CC0 texture.
Source Ractapopulous
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Continuing the geometric trend, here is one more.
Source Mike Warner
Simple wide squares with a small indent. Fits all.
Source Petr Šulc.
It’s okay to be square! A nice light gray pattern with random squares.
Source Waseem Dahman
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Prismatic Isometric Cube Extra Pattern No Background
Source GDJ
Not the most creative name, but it’s a good all-purpose light background.
Source Dmitry
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
From a drawing in 'Bond Slaves. The story of a struggle.', Isabella Varley, 1893.
Source Firkin
Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
The tile this is based on was adapted from an image that was uploaded to Pixabay by frolicsomepl. It can be had in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin