A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
A version without colours blended together to give a different look.
Source Firkin
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
ZeroCC tileable stone texture, edited from pixabay. CC0
Source Sojan Janso
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Embossed lines and squares with subtle highlights.
Source Alex Parker
Seamless SVG vector and JPG backgrounds with faded diagonal stripes. The colors are editable.
Source V. Hartikainen
Prismatic Groovy Concentric Background 2
Source GDJ
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
Source GDJ
This one is so simple, yet so good. And you know it. Has to be in the collection.
Source Gluszczenko
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
Prismatic Groovy Concentric Background
Source GDJ
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Fix and cc0 to get the tile this is based on.
Source SliverKnight
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
Zero CC asphalt, pavement, texture, photographed and made by me. CC0 WARNING I FOUND A SEAM ON THIS TEXTURE
Source Sojan Janso
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
To get the tile this is made up from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin