Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
This one has rusty dark brown texture.
Source V. Hartikainen
Prismatic Triangular Background Design Mark II 5
Source GDJ
Redrawn based on a drawing in 'По Сѣверо-Западу Россіи' Konstantin Sluchevsky, 1897.
Source Firkin
A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
Inspired by a pattern found in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
A new one called white wall, not by me this time.
Source Yuji Honzawa
An abstract web texture of a polished blue stone (or does it look more like ice).
Source V. Hartikainen
Psychedelic Geometric Background No Black
Source GDJ
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Alternative colour scheme. 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
The starting point for this was drawn on the web site steamcoded.org/PolyskelionMaker.svg
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
This is a remix of "blue wave-seigaiha".I hope this subtle color version of Seigaiha would be suitable for background .
Source Yamachem
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra