Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Remixed from a PNG that was uploaded to Pixabay by gingertea
Source Firkin
White fabric looking texture with some nice random wave features.
Source Hendrik Lammers
ZeroCC tileable stone texture, edited from pixabay. CC0
Source Sojan Janso
Here's a subtle marble-like background for use on websites.
Source V. Hartikainen
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Did anyone say The Hoff? This pattern is in no way related to Baywatch.
Source Josh Green
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
A seamless web texture of "green stone".
Source V. Hartikainen
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
Everyone needs some stardust. Sprinkle it on your next project.
Source Atle Mo
The following repeating website background is colored in a blue gray color and resembles a concrete wall or something similar to it.
Source V. Hartikainen
The name Paisley reminds me of an old British servant. That’s just me.
Source Swetha
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A seamless pattern formed from miutopia's cakes on a tablecloth.
Source Firkin
Floral patterns might not be the hottest thing right now, but you never know when you need it!
Source Lauren
An abstract pale yellow paper-like background with stains colored in yellow and green.
Source V. Hartikainen
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars
Same as gray sand but lighter. A sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
Abstract Tiled Background Extended 12
Source GDJ
Derived from a JPG that was uploaded to Pixabay by ractapopulous
Source Firkin
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Prismatic Abstract Background Design
Source GDJ
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight