Simple wide squares with a small indent. Fits all.
Source Petr Šulc.
Prismatic Geometric Pattern Background No Black
Source GDJ
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
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
A dark pattern made out of 3×3 circles and a 1px shadow. This works well as a carbon texture or background.
Source Atle Mo
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
Black brick wall pattern. Brick your site up!
Source Alex Parker
Number five from the same submitter, makes my job easy.
Source Dima Shiper
This is the remix of "Colorful Floral Pattern Background 3" uploaded by "GDJ". Thanks.
Source Yamachem
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A seamless paper background texture colored in pale yellow. This seamless texture is ideal for those who need a yellow background image for their website. The texture resembles paper.
Source V. Hartikainen
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Greyscale version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
Colorful Floral Background No Black
Source GDJ
Derived from an image that was uploaded to Pixabay by TheDigitalArtist
Source Firkin
Prismatic Hexagonalism Pattern No Background
Source GDJ
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
Looks like an old wall. I guess that’s it then?
Source Viahorizon
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Paper model of a tetrahedron. Modelo de papel de um tetraedro.
Source laobc