More Textures
Diamond pattern 2 (colour 6) #2261
 Colorful  CC 0

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

Source Firkin

White Brick Wall #593
 Wall  CC BY-SA 3.0

If you’re sick of the fancy 3D, grunge and noisy patterns, take a look at this flat 2D brick wall.

Source Listvetra

Prismatic Curved Diamond Pattern 7 No Background@2X #548
 Noise  CC 0

Prismatic Curved Diamond Pattern 7 No Background

Source GDJ

Checkered Light Emboss #280
 Grid  CC BY-SA 3.0

Sort of like the Photoshop transparent background, but better!

Source Alex Parker

Background pattern purple #1946
 Colorful  CC 0

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

Source Firkin

Vintage pattern 2 #2295
 Yellow  CC 0

Inspired by a pattern seen on a public domain image of a very old tile. To get the unit cell, select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

Prismatic Dots Background 6 #511
 Dark  CC 0

Prismatic Dots Background 6

Source GDJ

Prismatic Diamond Background 6 #383
 Diamond  CC 0

Prismatic Diamond Background 6

Source GDJ

Decorative divider 218 #2232
 Dark  CC 0

Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.

Source Firkin

60º lines@2X #26
 Light  CC BY-SA 3.0

Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.

Source Atle Mo

Soft Kill@2X #319
 Dark  CC BY-SA 3.0

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

Source Factorio.us Collective

Background pattern 333 #1741
 Noise  CC 0

The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i

Source Firkin

Background pattern 227 #2314
 Yellow  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 215 (colour 3) #2369
 Pink  CC 0

A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.

Source Firkin

Noisy@2X #46
 Paper  CC BY-SA 3.0

Looks a bit like concrete with subtle specks spread around the pattern.

Source Mladjan Antic