Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
Geometric lines are always hot, and this pattern is no exception.
Source Listvetra
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
8 by 8 pixels, and just what the title says.
Source pixilated
Remixed from a drawing in 'Incidents on a Journey through Nubia to Darfoor', F. Ensor, 1891.
Source Firkin
Pixel by pixel, sharp and clean. Very light pattern with clear lines.
Source M.Ashok
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
More Japanese-inspired patterns, Gold Scales this time.
Source Josh Green
Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
If you need a green background for your blog/website, try this one. Remember that Green Striped Background is seamlessly tileable.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Fix and cc0 to get the tile this is based on.
Source SliverKnight
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
A seamless light gray paper texture with horizontal double lines.
Source V. Hartikainen
Honestly, who does not like a little pipe and mustache?
Source Luca Errico