A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
Same classic 45-degree pattern, dark version.
Source Luke McDonald
Medium gray pattern with small strokes to give a weave effect.
Source Catherine
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
A rusty grunge background for websites. Feel free to use it in your site's theme.
Source V. Hartikainen
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
Element of beach pattern with background.
Source Rones
Medium gray fabric pattern with 45-degree lines going across.
Source Atle Mo
A set of paper filters. The base texture is generated the same way, only the compositing mode is varied.
Source Lazur URH
Abstract Tiled Background Extended 6
Source GDJ
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
From a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Tiny, tiny 3D cubes. Reminds me of the good old pattern from k10k.
Source Etienne Rallion
Scanned some rice paper and tiled it up for you. Enjoy.
Source Atle Mo
Dark and hard, just the way we like it. Embossed triangles makes a nice pattern.
Source Ivan Ginev
Prismatic Basic Pattern 2 No Background
Source GDJ
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
The image depicts a seamless pattern which includes hexagonally-aligned gourds with BG in light-brown.
Source Yamachem
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady