Carbon Fiber #3
Carbon CC BY-SA 3.0A dark pattern made out of 3×3 circles and a 1px shadow. This works well as a carbon texture or background.
Source Atle Mo
More Textures
Subtle Dark Vertical #607
Dark CC BY-SA 3.0Classic vertical lines, in all its subtlety.
Source Cody L
Tree and bird pattern #1983
Dark CC 0From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Fabric pattern 3 (colour 4) #2384
Fabric CC 0Alternative 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
Leafy pattern 4 #1915
Green CC 0Remixed from a drawing in 'Hungary. A guide book. By several authors', 1890.
Source Firkin
Dark Wall #817
Dark CC BY-SA 3.0Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
Embossed Paper #731
Paper CC BY-SA 3.0One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
Prismatic Groovy Concentric Background 5 #465
Dark CC 0Prismatic Groovy Concentric Background 5
Source GDJ
Dark Mosaic@2X #122
Dark CC BY-SA 3.0Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
Prismatic Basic Pattern 2 No Background #447
Noise CC 0Prismatic Basic Pattern 2 No Background
Source GDJ
Background pattern 225 (colour 2) #2326
Yellow CC 0Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Background pattern 215 (colour 2) #2370
Blue CC 0A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Light Honeycomb #59
Light CC BY-SA 3.0Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
Prismatic Groovy Concentric Background 4 #461
Noise CC 0Prismatic Groovy Concentric Background 4
Source GDJ
Decorative divider 284 #1848
Dark CC 0From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Frozen Surface With Diagonal Stripes #912
Stripes CC BY-SA 3.0This light background pattern has a texture of "frozen" surface with diagonal stripes. Here's an yet another addition to the collection of free website backgrounds.
Source V. Hartikainen
Pinetree in tortoiseshell(亀甲松) #2538
Dark CC 0The 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
Low Contrast Linen@2X #864
Dark CC BY-SA 3.0A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
Background pattern 310 #1862
Red CC 0Based on an image that was uploaded to Pixabay by devanath
Source Firkin
Worn Dots #709
Fabric CC BY-SA 3.0These dots are already worn for you, so you don’t have to.
Source Matt McDaniel