A free seamless background with pink spots.
Source V. Hartikainen
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
Honestly, who does not like a little pipe and mustache?
Source Luca Errico
Remixed from a vector adapted from a jpg on Pixabay. The tile this is constructed from can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A version without colours blended together to give a different look.
Source Firkin
Used correctly, this could be nice. Used in a bad way, all hell will break loose.
Source Atle Mo
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
This makes me wanna shoot some pool! Sweet green pool table pattern.
Source Caveman
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
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
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A dark metallic background with a pattern of stamped dots. Here's a dark "metallic" background pattern for you.
Source V. Hartikainen
From a drawing in 'Kingsdene', Maria Fetherstonehaugh, 1878.
Source Firkin
A pale yellow background pattern with vertical stripes. The stripes are partially faded. I think this background image turned out pretty well, especially those faded stripes.
Source V. Hartikainen
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
Seamless Prismatic Pythagorean Line Art Pattern No Background. A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ