Looks like an old rug or a computer chip.
Source Patutin Sergey
The classic notebook paper with horizontal stripes.
Source Are Sundnes
Used in small doses, this could be a nice subtle pattern. Used on a large surface, it’s dirty!
Source Paul Reulat
This one is something special. I’d call it a flat pattern, too. Very well done, sir!
Source GetDiscount
The file was named striped lens, but hey – Translucent Fibres works too.
Source Angelica
I’m guessing this is related to the Sony Vaio? It’s a nice pattern no matter where it’s from.
Source Zigzain
This pattern comes in orange, and it looks as if it is "made of glass".
Source V. Hartikainen
This is the remix of "blue wave-seigaiha".The image depicts a seamless pattern of the front upper part of Japanese five yen coin which is used currently.This design represents a rice with ripe golden ears.
Source Yamachem
Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.
Source Eady
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Prismatic Geometric Tessellation Pattern 3 No Background
Source GDJ
Zero CC tileable ground cracked, crackled, texture, made by me.
Source Sojan Janso
ZeroCC tileabel stone granite texture, edited from pixabay. CC0
Source Sojan Janso
Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
Source Firkin
Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Prismatic Floral Pattern 3 Variation 3 No Background
Source GDJ
Based on an image that was uploaded to Pixabay by devanath
Source Firkin
The image depicts meshed silhouettes of various things.The original image is an OCAL clipart called "Enter FOSSASIA 2016 #IoT T-shirt Design Contest" uploaded by "openclipart".Thanks.
Source Yamachem
Prismatic Groovy Concentric Background
Source GDJ
Three shades of gray makes this pattern look like a small carbon fiber surface. Great readability even for small fonts.
Source Atle Mo
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady