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
This background pattern contains a seamless texture of bark. It's not very realistic, but I think it looks quite nice.
Source V. Hartikainen
From a drawing in 'From Snowdon to the Sea. Striking stories of North and South Wales', Marie Trevelyan, 1895.
Source Firkin
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
Just what the name says, paper fibers. Always good to have.
Source Heliodor jalba
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
Used a cherry by doctormo to make this seamless pattern
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
Not even 1kb, but very stylish. Gray thin lines.
Source Struck Axiom
A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.
Source Firkin
A seamless pattern based on a rectangular tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Zero CC tileable hard cover cells, skin like, book texture. 4K, Scanned and made by me CC0
Source Sojan Janso
"Beige Stone", Tileable Texture.
Source V. Hartikainen
Floral patterns will never go out of style, so enjoy this one.
Source Lasma
Has nothing to do with toast, but it’s nice and subtle.
Source Pippin Lee
A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.
Source Firkin