Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
Just like your old suit, all striped and smooth.
Source Alex Berkowitz
A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Three shades of gray makes this pattern look like a small carbon fiber surface. Great readability even for small fonts.
Source Atle Mo
This is indeed a bit strange, but here’s to the crazy ones!
Source Christopher Buecheler
A dark metallic background with a pattern of stamped dots. Here's a dark "metallic" background pattern for you.
Source V. Hartikainen
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
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
A repeating background of thick textured paper. Actually, it turned out to look like something between a paper and fabric.
Source V. Hartikainen
A seamlessly repeating background pattern of wood. The image is procedurally generated, and, I think, it's turned out quite well.
Source V. Hartikainen
Nicely crafted paper pattern, although a bit on the large side (500x593px).
Source Blaq Annabiosis
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
Bumps, highlight and shadows – all good things.
Source Badhon Ebrahim
Prismatic Snowflakes Pattern No Background
Source GDJ
Prismatic Geometric Pattern Background 2
Source GDJ
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 6 No Background
Source GDJ
Remixed from a drawing in 'Incidents on a Journey through Nubia to Darfoor', F. Ensor, 1891.
Source Firkin