A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
All good things come in threes, so I give you the third in my little concrete wall series.
Source Atle Mo
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
Prismatic Geometric Pattern Variation 2 With 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
Prismatic Hexagonalist Pattern No Background
Source GDJ
Remix from a drawing in 'Ostatnie chwile powstania styczniowego', Zygmunt Sulima, 1887.
Source Firkin
Inspired by a drawing in 'Poems', James Smith, 1881.
Source Firkin
Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.
Source Badhon Ebrahim
Number five from the same submitter, makes my job easy.
Source Dima Shiper
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
A lovely light gray pattern with stripes and a dash of noise.
Source V. Hartikainen
A nice and simple white rotated tile pattern.
Source Another One
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A free grid paper background pattern for using on web sites.
Source V. Hartikainen
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
Prismatic Abstract Background Design
Source GDJ
I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel