Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
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
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
Farmer could be some sort of fabric pattern, with a hint of green.
Source Fabian Schultz
More carbon fiber for your collections. This time in white or semi-dark gray.
Source Badhon Ebrahim
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
This one needs to be used in small areas; you can see it repeat.
Source Luca
Remixed from a drawing in 'Kulturgeschichte der Deutschen im Mittelalter' Franz von Loeher, 1891. The unit tile can be had by selecting the rectangle in Inkscape and using shift-alt-i
Source Firkin
Prismatic Abstract Geometric Background 4
Source GDJ
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Light gray pattern with an almost wall tile-like appearance.
Source Markus Tinner
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
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
Retro Circles Background 5 No Black
Source GDJ
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab