Dark Brick Pattern #1032
 Stone  CC BY-SA 3.0

A seamless pattern of dark bricks. Maybe it's not very realistic, but it looks good in my opinion.

Source V. Hartikainen

 More Textures
Prismatic Geometric Pattern Background 2 No Black #410
 Noise  CC 0

Prismatic Geometric Pattern Background 2 No Black

Source GDJ

Prismatic Groovy Concentric Background 3 No Black #459
 Noise  CC 0

Prismatic Groovy Concentric Background 3 No Black

Source GDJ

Decorative divider 201 #2421
 Dark  CC 0

From a drawing in 'Heroes of North African Discovery', Nancy Meugens, 1894.

Source Firkin

45-Degree [email protected] #2
 Fabric  CC BY-SA 3.0

Medium gray fabric pattern with 45-degree lines going across.

Source Atle Mo

Retro Squares Background 4 #418
 Dark  CC 0

Retro Squares Background 4

Source GDJ

Background pattern 224 (colour 6) #2337
 Colorful  CC 0

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

Source Firkin

Rubber Grip #101
 Dark  CC BY-SA 3.0

A very slick dark rubber grip pattern, sort of like the grip on a camera.

Source Sinisha

Decorative divider 189 #2518
 Dark  CC 0

From a drawing in 'Uit de geschiedenis der Heilige Stede te Amsterdam', Yohannes Sterck, 1898.

Source Firkin

stripe seamless pattern #2279
 Dark  CC 0

The image depicts a seamless pattern which was made using stripe-like things including borders.I used OCAL cliparts called "Blue Greek Key With Lines Border" uploaded by "GR8DAN" and "daisy border" uploaded by "johnny_automatic".Thanks.

Source Yamachem

gourd seamless pattern #2277
 Brown  CC 0

The image depicts a seamless pattern which includes hexagonally-aligned gourds with BG in light-brown.

Source Yamachem

Escheresque #777
 Light  CC BY-SA 3.0

Cubes as far as your eyes can see. You know, because they tile.

Source Jan Meeus

Swirl #947
 Light  CC BY-SA 3.0

The name tells you it has curves. Oh yes, it does!

Source Peter Chon

Aged Grid Paper Background #1072
 Paper  CC BY-SA 3.0

A seamless web background with texture of aged grid paper.

Source V. Hartikainen

Wood 1 #1443
 Wood  CC 0

Gamedev - Wood Textures. CC0 License.

Source Davit Masia

Retro [email protected] #894
 Gray  CC BY-SA 3.0

A slightly more textured pattern, medium gray. A bit like a potato sack?

Source Bilal Ketab

Desert Camo Print #255
 Fabric  CC 0

Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.

Source Eady

Colorful Floral Background 3 No [email protected] #486
 Light  CC 0

Colorful Floral Background 3 No Black

Source GDJ

Diagonal [email protected] #182
 Fabric  CC BY-SA 3.0

A simple but elegant classic. Every collection needs one of these.

Source Christopher Burton

Concretia 1 #1408
 Gray  CC 0

Gamedev - Concrete Textures. CC0 License.

Source Davit Masia

White [email protected] #640
 Fabric  CC BY-SA 3.0

I took the liberty of using Dmitry’s pattern and made a version without perforation.

Source Atle Mo

Blizzard #663
 Paper  CC BY-SA 3.0

This is so subtle I hope you can see it! Tweak at will.

Source Alexandre Naud

Prismatic Hexagonalist Pattern No Background #390
 Light  CC 0

Prismatic Hexagonalist Pattern No Background

Source GDJ

[email protected] #349
 Light  CC BY-SA 3.0

White circles connecting on a light gray background.

Source Mark Collins

[email protected] #62
 Dark  CC BY-SA 3.0

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

Source Chris Baldie

More Rough Wood 2 #1428
 Wood  CC 0

Gamedev - Wood Textures. CC0 License.

Source Davit Masia

Geometric pattern #2004
 Grid  CC 0

A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i

Source Firkin

Skeletal Weave #931
 Light  CC BY-SA 3.0

Imagine you zoomed in 1000X on some fabric. But then it turned out to be a skeleton!

Source Angelica

Large Leather #649
 Paper  CC BY-SA 3.0

More leather, and this time it’s bigger! You know, in case you need that.

Source Elemis

Stone Wall & Dark #1496
 Stone  CC 0

Incoming catena. Stone & well. CC0 texture.

Source Unknow

Gravel 3 Roughness #1472
 Dark  CC 0

Gravel style CC0 texture.

Source StruffelProductions