Retro Squares Background 2@2X #417
 Noise  CC 0

Retro Squares Background 2

Source GDJ

 More Textures
Prismatic Abstract Line Art Pattern Background #565
 Dark  CC 0

Prismatic Abstract Line Art Pattern Background

Source GDJ

Batthern@2X #325
 Grid  CC BY-SA 3.0

Sometimes simple really is what you need, and this could fit you well.

Source Factorio.us Collective

Background pattern 220 #2360
 Dark  CC 0

A seamless pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Derived from a design in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.

Source Firkin

Carbon Fiber@2X #4
 Carbon  CC BY-SA 3.0

A dark pattern made out of 3×3 circles and a 1px shadow. This works well as a carbon texture or background.

Source Atle Mo

Background pattern 290 #1932
 Dark  CC 0

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

Source Firkin

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

“Transparent” Background Pattern@2X #494
 Light  CC 0

An emulated “transparent” background pattern, like that of all kinds of computer graphics software.

Source AdamStanislav