More Textures
Prismatic Abstract Geometric Background 4 No Black #441
 Dark  CC 0

Prismatic Abstract Geometric Background 4 No Black

Source GDJ

Green Fibers #91
 Dark  CC BY-SA 3.0

The green fibers pattern will work very well in grayscale as well.

Source Matteo Di Capua

Retro Squares Background 8 #398
 Noise  CC 0

Retro Squares Background 8

Source GDJ

Soft Kill@2X #319
 Dark  CC BY-SA 3.0

Pattern #100! A black classic knit-looking pattern.

Source Factorio.us Collective

Background pattern 315 (colour 4) #1842
 Colorful  CC 0

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

Source Firkin

Graphy #350
 Grid  CC BY-SA 3.0

Looks like a technical drawing board: small squares forming a nice grid.

Source We Are Pixel8

"Gold Buttons", Pale Yellow BG Pattern #1215
 Yellow  CC BY-SA 3.0

This yellow background consists of a pattern of glossy gold buttons arranged in polka dot style on a seamless texture. Here's a pale yellow background pattern. Feel free to use it for your needs!

Source V. Hartikainen

Bright Multicolored Floral Background@2X #560
 Noise  CC 0

Bright Multicolored Floral Background by Karen Arnold from PDP.

Source GDJ

Wood Pattern #370
 Wood  CC BY-SA 3.0

One of the few full-color patterns here, but this one was just too good to pass up.

Source Alexey Usoltsev

Prismatic Polka Dots Mark II 3 No Background #534
 Noise  CC 0

Prismatic Polka Dots Mark II 3 No Background

Source GDJ

Background pattern 309 (colour 2) #1865
 Blue  CC 0

Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.

Source Firkin