Micro Carbon #7
 Carbon  CC BY-SA 3.0

Three shades of gray makes this pattern look like a small carbon fiber surface. Great readability even for small fonts.

Source Atle Mo

 More Textures
Prismatic Curved Diamond Pattern 3 No Background@2X #540
 Diamond  CC 0

Prismatic Curved Diamond Pattern 3 No Background

Source GDJ

Zig-zag pattern 6 #2413
 Grid  CC 0

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

Background pattern 328 (colour 2) #1800
 Green  CC 0

To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i

Source Firkin

Rice Paper #338
 Paper  CC BY-SA 3.0

Scanned some rice paper and tiled it up for you. Enjoy.

Source Atle Mo

Grilled Noise #581
 Fabric  CC BY-SA 3.0

You could get a bit dizzy from this one, but it might come in handy.

Source Dertig Media

Vintage pattern #1959
 Grid  CC 0

Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.

Source Firkin

Tactile Noise@2X #6
 Dark  CC BY-SA 3.0

A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.

Source Atle Mo

Triangular Psychosis 2 #234
 Noise  CC 0

A colorful triangular background, variation 2.

Source GDJ

Flowery pattern 4 #2328
 Colorful  CC 0

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

Padded@2X #62
 Dark  CC BY-SA 3.0

A beautiful dark padded pattern, like an old classic sofa.

Source Chris Baldie

Noisy #45
 Paper  CC BY-SA 3.0

Looks a bit like concrete with subtle specks spread around the pattern.

Source Mladjan Antic

Hibiscus Flowers Seamless Background #229
 Fabric  CC 0

PDP

Source GDJ

Seamless Prismatic Pythagorean Line Art Pattern No Background #569
 Light  CC 0

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

Colorful Floral Background 3 No Black #485
 Light  CC 0

Colorful Floral Background 3 No Black

Source GDJ