A simple example on using clones. You can generate a nice base for a pattern fill quickly with it.
Source Lazur URH
A seamless pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Prismatic Geometric Pattern Variation 2 With Background
Source GDJ
Psychedelic Geometric Background No Black
Source GDJ
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
Pattern formed from simple shapes. Black version.
Source Firkin
Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
The image depicts a pattern of regular hexagon.As I made to use it for myself,I want to others to use it.Speaking about the ratio of the image, height : width = 2 : √3(1.732...)Ridiculous to say,I realized later that this image is not honey comb pattern.I have to slide the second row.
Source Yamachem
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
From an image on opengameart.org shared by rubberduck.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
This is a remix of "blue wave-seigaiha".I hope this subtle color version of Seigaiha would be suitable for background .
Source Yamachem
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
Your eyes can trip a bit from looking at this – use it wisely.
Source Michal Chovanec
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
The original enhanced with some gradients.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
A dark metal plate with an embossed grid pattern and a bit of rust. Here's a dark metal plate texture for use as a tiled background on web pages.
Source V. Hartikainen