This is a hot one. Small, sharp and unique.
Source GraphicsWall
Prepared mostly as a raster in Paint.net and vectorised.
Source Firkin
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
Prismatic Floral Background No Black
Source GDJ
A hint of orange color, and some crossed and embossed lines.
Source Adam Anlauf
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Actually remixed from a pattern on Pixabay. But then noticed a very similar one on Openclipart.org uploaded by btj51q2.
Source Firkin
A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
Here's a new paper-like background for free use on personal and commercial projects (this applies to all background patterns here).
Source V. Hartikainen
From a drawing in 'Heroes of North African Discovery', Nancy Meugens, 1894.
Source Firkin
A white version of the very popular linen pattern.
Source Ant Ekşiler
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
This ons is quite old school looking. Retro, even. I like it.
Source Arno Declercq
Number 3 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
A seamless pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Derived from a design in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
Simple wide squares with a small indent. Fits all.
Source Petr Šulc.
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin