Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
A simple circle. That’s all it takes. This one is even transparent, for those who like that.
Source Saqib
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A bit strange this one, but nice at the same time.
Source Diogo Silva
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A seamless pattern recreated from an image on Pixabay. It is reminiscent of parquet flooring and is formed from a square tile, which can be recovered in Inkscape by selecting the ungrouped rectangle and using shift-alt-I together.
Source Firkin
Abstract Ellipses Background Grayscale
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A seamless pale yellow paper background with a pattern of animal tracks.
Source V. Hartikainen
Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
Sort of like the Photoshop transparent background, but better!
Source Alex Parker
Prismatic Isometric Cube Extra Pattern No Background
Source GDJ
A simple circle. That’s all it takes. This one is even transparent, for those who like that.
Source Saqib
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
From a drawing in 'Bond Slaves. The story of a struggle.', Isabella Varley, 1893.
Source Firkin
ZeroCC tileable stone texture, edited from pixabay. CC0
Source Sojan Janso
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
The texture of this background image has some similarities with leather, and it's colored in a dark brown color. So, if you are looking for a dark brown background image for your website, this may be an option for you.
Source V. Hartikainen
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Sort of reminds me of those old house wallpapers.
Source Tish
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous