Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
Prismatic Basic Pattern 2 No Background
Source GDJ
This light background pattern has a texture of "frozen" surface with diagonal stripes. Here's an yet another addition to the collection of free website backgrounds.
Source V. Hartikainen
White handmade paper pattern with small bumps.
Source Marquis
Here is a new seamless wood texture for using as blog or website backgrounds.
Source V. Hartikainen
Colored maple leaves scattered on a surface. This is tileable, so it can be used as a background or wallpaper.
Source Eady
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
This is the remix of "Background pattern 115" uploaded by "Firkin".Thanks.
Source Yamachem
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
Tweed is back in style – you heard it here first. Also, the @2X version here is great!
Source Simon Leo
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
Feel free to download and use it, or see the rest of the dark background patterns that I have made. Anyway, I hope you will find something that you like.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
Prismatic Groovy Concentric Background 2
Source GDJ
Prismatic Chevrons Pattern 5 With Background
Source GDJ
Alternative colour scheme to the original.
Source Firkin