Background pattern 225 (colour 3) #2325
 Pink  CC 0

Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.

Source Firkin

 More Textures
Grunge Wall #81
 Wall  CC BY-SA 3.0

Light gray grunge wall with a nice texture overlay.

Source Adam Anlauf

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

Paper 1 #15
 Paper  CC BY-SA 3.0

A slightly grainy paper pattern with small horizontal and vertical strokes.

Source Atle Mo

pattern cleanup filtered #151
 Noise  CC 0

With a fabric filter added.Tags

Source Lazur URH

Prismatic Abstract Geometric Background 5 No Black #402
 Noise  CC 0

Prismatic Abstract Geometric Background 5 No Black

Source GDJ

Diamond pattern (colour 2) #2284
 Green  CC 0

From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.

Source Firkin

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

Background pattern 1 #220
 Noise  CC 0

A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.

Source Firkin

Zig-zag pattern 5 #2414
 Grid  CC 0

A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.

Source Firkin

Light Aluminum #304
 Wall  CC BY-SA 3.0

Used correctly, this could be nice. Used in a bad way, all hell will break loose.

Source Atle Mo