More Textures
Diamond pattern (colour 7) #2274
 Red  CC 0

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

Source Firkin

White Paperboard@2X #375
 Fabric  CC BY-SA 3.0

Could be paper, could be a Polaroid frame – up to you!

Source Chaos

Cardboard@2X #279
 Paper  CC BY-SA 3.0

A good starting point for a cardboard pattern. This would work well in a variety of colors.

Source Atle Mo

Prismatic Isometric Cube Extra Pattern No Background #405
 Light  CC 0

Prismatic Isometric Cube Extra Pattern No Background

Source GDJ

Retro Squares Background 2 #416
 Noise  CC 0

Retro Squares Background 2

Source GDJ

Mosaic Gems Background #526
 Noise  CC 0

Mosaic Gems Background

Source GDJ

Psychedelic Geometric Background #381
 Noise  CC 0

Psychedelic Geometric Background.

Source GDJ

Zodiac pattern #2407
 Colorful  CC 0

A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i

Source Firkin

Prismatic Abstract Geometric Background 4 #271
 Noise  CC 0

Prismatic Abstract Geometric Background 4

Source GDJ