More Textures
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

Triangular Psychosis 2 #234
 Noise  CC 0

A colorful triangular background, variation 2.

Source GDJ

Pinetree in tortoiseshell(亀甲松) #2538
 Dark  CC 0

The image depicts a seamless pattern of Japanese Edo pattern called "kikkou-matsu" or "亀甲松" meaning " tortoiseshell-pinetree".The real pinetree is like this: https://jp.pinterest.com/pin/500744052301065077/

Source Yamachem

Gold Scale #284
 Light  CC BY-SA 3.0

More Japanese-inspired patterns, Gold Scales this time.

Source Josh Green

Street Art Pattern #1196
 Concrete  CC BY-SA 3.0

Looks as if it's spray painted on the wall. You can be sure that this pattern will seamlessly fill your backgrounds on web pages.

Source V. Hartikainen

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

Abstract Arbitrary Geometric Background derived from an image on Pixabay.

Source GDJ

Axiom Pattern@2X #331
 Grid  CC BY-SA 3.0

Not even 1kb, but very stylish. Gray thin lines.

Source Struck Axiom

Floral pattern 15 #1753
 Dark  CC 0

The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i

Source Firkin

Beige Paper #83
 Paper  CC BY-SA 3.0

This was submitted in a beige color, hence the name. Now it’s a gray paper pattern.

Source Konstantin Ivanov