It’s a hole, in a pattern. On your website. Dig it!
Source Josh Green
Subtle scratches on a light gray background.
Source Andrey Ovcharov
Here's a subtle marble-like background for use on websites.
Source V. Hartikainen
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
Prismatic Geometric Pattern Background 2
Source GDJ
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Prismatic Curved Diamond Pattern 2 No Background
Source GDJ
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Classic vertical lines, in all its subtlety.
Source Cody L
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
Green Background Pattern
Source V. Hartikainen