Prismatic Groovy Concentric Background
Source GDJ
A floral background formed from numerous clones of flower 117.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
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
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
Submitted in a cream color, but you know how I like it.
Source Devin Holmes
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
One more brick pattern. A bit more depth to this one.
Source Benjamin Ward