Green Web Background, Seamless tile.
Source V. Hartikainen
A slightly grainy paper pattern with small horizontal and vertical strokes.
Source Atle Mo
Not the most creative name, but it’s a good all-purpose light background.
Source Dmitry
A very dark asfalt pattern based off of a photo taken with my iPhone.
Source Atle Mo
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
CC0 and seamless wellington boot pattern.
Source SliverKnight
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
Inspired by a drawing in 'Poems', James Smith, 1881.
Source Firkin
High detail stone wall with minor cracks and specks.
Source Projecteightyfive
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Same classic 45-degree pattern, dark version.
Source Luke McDonald
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A free seamless background with pink spots.
Source V. Hartikainen
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
Remixed from a drawing in 'Hungary. A guide book. By several authors', 1890.
Source Firkin
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
You know you love wood patterns, so here’s one more.
Source Richard Tabor
The base gradient edited so now more details are rendered.
Source Lazur URH
The original enhanced with one of Inkscapes's filters.
Source Firkin