Background pattern 306 (colour 4) #1877
 Colorful  CC 0

Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.

Source Firkin

 More Textures
Seamless Prismatic Pythagorean Line Art Pattern No Background #569
 Light  CC 0

Seamless Prismatic Pythagorean Line Art Pattern No Background. A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).

Source GDJ

Fabric pattern 3 (colour 5) #2383
 Fabric  CC 0

Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.

Source Firkin

Decorative divider 274 #1922
 Dark  CC 0

Redrawn based on a drawing in 'По Сѣверо-Западу Россіи' Konstantin Sluchevsky, 1897.

Source Firkin

Abstract Arbitrary Geometric Background@2X #498
 Noise  CC 0

Abstract Arbitrary Geometric Background derived from an image on Pixabay.

Source GDJ

Fleurs-de-lys pattern 2 (colour) #2204
 Colorful  CC 0

Colour version of the original pattern inspired by the front cover of 'Old and New Paris', Henry Edwards, 1894.

Source Firkin

Type #276
 Dark  CC BY-SA 3.0

The perfect pattern for all your blogs about type, or type-related matters.

Source Atle Mo

Prismatic Polka Dots 3 No Background@2X #529
 Noise  CC 0

Prismatic Polka Dots 3 No Background

Source GDJ

Prismatic Floral Background No Black@2X #476
 Light  CC 0

Prismatic Floral Background No Black

Source GDJ

Paper 2 #21
 Paper  CC BY-SA 3.0

New paper pattern with a slightly organic feel to it, using some thin threads.

Source Atle Mo

Background pattern blue #1949
 Blue  CC 0

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

Source Firkin

Prismatic Isometric Cube Wireframe Pattern No Background@2X #500
 Light  CC 0

Prismatic Isometric Cube Wireframe Pattern No Background

Source GDJ

Transparent Square Tiles #298
 Grid  CC BY-SA 3.0

The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.

Source Nathan Spady

Rough Cloth #312
 Fabric  CC BY-SA 3.0

More tactile goodness. This time in the form of some rough cloth.

Source Bartosz Kaszubowski

Tessellation 15 #2223
 Dark  CC 0

The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.

Source Firkin