The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees
A pattern drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
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
This is a remix of "geometrical pattern 01".
Source Yamachem
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
Inspired by a 1930s wallpaper pattern I saw on TV.
Source Firkin
Background Wall, Art Abstract, white Well & CC0 texture.
Source Ractapopulous
Prismatic Curved Diamond Pattern No Background
Source GDJ
A very dark spotted twinkle pattern for your twinkle needs.
Source Badhon Ebrahim
Prismatic Floral Background No Black
Source GDJ
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
From a drawing in 'A Life Interest', Mrs Alexander, 1888.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Real snow that tiles, not easy. This is not perfect, but an attempt.
Source Atle Mo
A nice looking light gray background pattern with diagonal stripes.
Source V. Hartikainen
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A seamless background pattern of dark brown wood planks.
Source V. Hartikainen
Zero CC tileable pine bark texture, photographed and made by me. CC0
Source Sojan Janso
Here's a tile-able wood background image for use in web design.
Source V. Hartikainen