Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Carbon fiber is never out of fashion, so here is one more style for you.
Source Alfred Lee
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
A seamless pattern with a unit cell drawn as a bitmap in Paint.net and vectorized in Vector Magic.
Source Firkin
Here's a seamless brown cork board background texture. Feel free to download or reshare if you like.
Source V. Hartikainen
A brown seamless wood texture in a form of stripe pattern. The result has turned out pretty well, in my opinion.
Source V. Hartikainen
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
A seamless background colored in pale orange. It has a paper like texture with diagonal grid pattern.
Source V. Hartikainen
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Less Black than we're painted', James Payn, 1884.
Source Firkin
A seamless textured paper for backgrounds. Colored in pale orange hues.
Source V. Hartikainen
Super detailed 16×16 tile that forms a beautiful pattern of straws.
Source Pavel