Small Crosses@2X #116
 Stripes  CC BY-SA 3.0

Sharp pixel pattern looking like some sort of fabric.

Source Dmitry

 More Textures
Dark Denim #29
 Dark  CC BY-SA 3.0

A dark denim looking pattern. 145×145 pixels.

Source Atle Mo

Colourful background #2010
 Colorful  CC 0

Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic

Source Firkin

Triangular Psychosis 4 #236
 Noise  CC 0

A colorful triangular background, variation 4.

Source GDJ

Prismatic Abstract Background Design #403
 Noise  CC 0

Prismatic Abstract Background Design

Source GDJ

Retro Squares Background 7 #397
 Noise  CC 0

Retro Squares Background 7

Source GDJ

Background pattern 227 (colour 3) #2312
 Pink  CC 0

A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.

Source Firkin

My Little Plaid #332
 Light  CC BY-SA 3.0

Repeating squares overlapping.

Source Pete Fecteau

Background pattern 270 #2061
 Dark  CC 0

A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i

Source Firkin

Rice Paper@2X #339
 Paper  CC BY-SA 3.0

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

Source Atle Mo

blue wave-seigaiha #2535
 Blue  CC 0

The image depicts the Japanese Edo pattern called "seigaiha" or "青海波" meaning "blue -sea- wave".I hope it's suitable for the summer season.

Source Yamachem

Medic Packaging Foil@2X #377
 Light  CC BY-SA 3.0

8 by 8 pixels, and just what the title says.

Source pixilated