Old Cardboard, Background Texture #1213
 Cardboard  CC BY-SA 3.0

A seamless background texture of old cardboard.

Source V. Hartikainen

 More Textures
Stone Wall & Yellow #1514
 Stone  CC 0

Incoming catena. Stone & well. CC0 texture.

Source Unknow

Triangular Psychosis 4 #236
 Noise  CC 0

A colorful triangular background, variation 4.

Source GDJ

Wood Stripe Pattern #888
 Wood  CC BY-SA 3.0

A brown seamless wood texture in a form of stripe pattern. The result has turned out pretty well, in my opinion.

Source V. Hartikainen

Grunge For Surfaces 6 #1403
 Dark  CC 0

Gamedev - Metal Textures. CC0 License.

Source Davit Masia

Background pattern 339 #1709
 Dark  CC 0

The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i

Source Firkin

Background pattern 202 (colour 2) #2489
 Green  CC 0

Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i

Source Firkin

Background pattern 257 #2137
 Dark  CC 0

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

Paper 2 #2113
 Paper  CC 0

CC0 textures, backgrounds.

Source SliverKnight

Rice Paper 2 #340
 Paper  CC BY-SA 3.0

One can never have too few rice paper patterns, so here is one more.

Source Atle Mo

Cork 1 #2108
 Unknow  CC 0

CC0 textures, backgrounds.

Source SliverKnight

Retro Intro #893
 Gray  CC BY-SA 3.0

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

Source Bilal Ketab

Background pattern brown #1945
 Brown  CC 0

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

Source Firkin

Stripy checkerboard pattern #1768
 Dark  CC 0

Simple combination of stripy squares with their negatively coloured counterparts

Source Firkin

Snow #627
 Wall  CC BY-SA 3.0

Real snow that tiles, not easy. This is not perfect, but an attempt.

Source Atle Mo

Prismatic Triangular Background Design Mark II [email protected] #788
 Dark  CC 0

Prismatic Triangular Background Design Mark II 5

Source GDJ

Square ornament 38 #2147
 Dark  CC 0

From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.

Source Firkin

Asfault 1 #1380
 Dark  CC 0

Gamedev - Asphalt textures. CC0 License.

Source Davit Masia

Ribbon pattern 2 (version 2, colour 2) #2038
 Colorful  CC 0

The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.

Source Firkin

Abstract Paper-Like Background With Colorful Stains #1226
 Yellow  CC BY-SA 3.0

An abstract pale yellow paper-like background with stains colored in yellow and green.

Source V. Hartikainen

Cork 3 #2110
 Unknow  CC 0

CC0 textures, backgrounds.

Source SliverKnight

Wild [email protected] #989
 Dark  CC BY-SA 3.0

Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.

Source Badhon Ebrahim

Seamless Gray Stone Background #1028
 Stone  CC BY-SA 3.0

This background image has seamless texture that resembles a surface of gray stone.

Source V. Hartikainen

Square ornament 37 #2177
 Dark  CC 0

Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.

Source Firkin

Arches #715
 Light  CC BY-SA 3.0

One more in the line of patterns inspired by Japanese/Asian styles. Smooth.

Source Kim Ruddock

Concretia 8 #1415
 Gray  CC 0

Gamedev - Concrete Textures. CC0 License.

Source Davit Masia

White [email protected] #1184
 Wall  CC BY-SA 3.0

Brushed aluminum, in a bright gray version. Lovely 2X as well.

Source Andre Schouten

Prismatic Groovy Concentric Background No [email protected] #452
 Noise  CC 0

Prismatic Groovy Concentric Background No Black

Source GDJ

Fabric pattern 3 (colour 6) #2382
 Fabric  CC 0

Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.

Source Firkin