The tile for this is based on a repeating unit close to a design on Pixabay. It can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
As the original image 's page size is too large for its image size, I remixed it.
Source Yamachem
A hint of orange color, and some crossed and embossed lines.
Source Adam Anlauf
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Embossed lines and squares with subtle highlights.
Source Alex Parker
A seamless web texture with illustration of pale color stains on canvas.
Source V. Hartikainen
A seamless pattern formed from a sports car on clker.com. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
Prismatic Abstract Geometric Background 4 No Black
Source GDJ
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
CC0 and seamless wellington boot pattern.
Source SliverKnight
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A seamless gray background texture suitable for use on websites. To me, it has the look of stone. Feel free to modify it to meet your needs (by making it a bit lighter or darker, for example).
Source V. Hartikainen
Prismatic Geometric Pattern Background No Black
Source GDJ
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Prismatic Abstract Background Design
Source GDJ
Prismatic Snowflakes Pattern No Background
Source GDJ
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
Used in small doses, this could be a nice subtle pattern. Used on a large surface, it’s dirty!
Source Paul Reulat