A slightly grainy paper pattern with small horizontal and vertical strokes.
Source Atle Mo
The image depicts a seamless pattern of a tortoise in tortoiseshell (hexagon).
Source Yamachem
An abstract texture of water. It's not perfect, but will do. You may download if you like it.
Source V. Hartikainen
Sharp pixel pattern looking like some sort of fabric.
Source Dmitry
Sharp diamond pattern. A small 24x18px tile.
Source Tom Neal
Stefan is hard at work, this time with a funky pattern of squares.
Source Stefan Aleksić
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Inspired by a drawing seen in 'City of Liverpool', James Picton, 1883.
Source Firkin
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
Derived from an image that was uploaded to Pixabay by starchim01
Source Firkin
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
A new take on the black linen pattern. Softer this time.
Source Atle Mo
From a drawing in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
Inspired by a JPG that was uploaded to Pixabay by kokon_art
Source Firkin
Here's an yet another background for websites, with a seamless texture of wood planks this time.
Source V. Hartikainen
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Sometimes you just need the simplest thing.
Source Fabricio
With a name like this, it has to be hot. Diagonal lines in light shades.
Source Isaac