Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
Derived from a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
More Japanese-inspired patterns, Gold Scales this time.
Source Josh Green
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
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 so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
Same as gray sand but lighter. A sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
Abstract Ellipses Background Grayscale
Source GDJ
Feel free to use this seamless background texture as a background on a web site. It's colored in a light pink color and is seamlessly tile-able.
Source V. Hartikainen
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Zero CC tileable grass texture, photographed and made by me. CC0
Source Sojan Janso
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Prismatic Floral Background No Black
Source GDJ
Love the style on this one, very fresh. Diagonal diamond pattern. Get it?
Source INS
Prismatic Hypnotic Pattern 2 No Background
Source GDJ