A light background pattern with diagonal stripes. Here's a simple light striped background for you.
Source V. Hartikainen
Zero CC bark from fur tree tileable texture, photographed and made by me. CC0
Source Sojan Janso
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
Used in small doses, this could be a nice subtle pattern. Used on a large surface, it’s dirty!
Source Paul Reulat
Psychedelic Geometric Background No Black
Source GDJ
This is a seamless pattern which is derived from a flower petal image.
Source Yamachem
From drawing in 'Musings in Maoriland', Thomas Bracken, 1890.
Source Firkin
Zero CC tileable Crackled Cement (streaks) texture, photographed and made by me. CC0
Source Sojan Janso
Zero CC tileable brick texture, photographed and made by me. CC0
Source Sojan Janso
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
I have no idea how to describe this one, but it’s light and delicate.
Source JBasoo
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
This tiled background comes in red and consists of tiles that look like gemstones. It is more for blogs or social profiles, I think.
Source V. Hartikainen
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
The classic notebook paper with horizontal stripes.
Source Are Sundnes
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
From a design in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin
Inspired by a pattern seen on a public domain image of a very old tile. To get the unit cell, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Prismatic Geometric Pattern Variation 2 With Background
Source GDJ