Non-seamless pattern drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
Background formed from the original with an emboss effect
Source GDJ
Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
This is the remix of "Tileable Wave Pattern 2" uploaded by "Arvin61r58".Thanks.I added a wire-mesh fence seamless pattern as a lower layer.
Source Yamachem
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
Prismatic Polka Dots Mark II No Background
Source GDJ
This ladies and gentlemen, is texturetastic! Love it.
Source Adam Pickering
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin
Fake or not, it’s quite luxurious.
Source Factorio.us Collective
A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
Sounds like something from World of Warcraft. Has to be good.
Source Tony Kinard
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
Medium gray pattern with small strokes to give a weave effect.
Source Catherine
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
Derived from an image that was uploaded to Pixabay by darkmoon1968
Source Firkin
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
The edges of all the red objects line up either vertically or horizontally, but it doesn't appear so. Made from a square tile that can be got by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Geometric Tessellation Pattern No Background
Source GDJ