The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
You just can’t get enough of the fabric patterns, so here is one more for your collection.
Source Krisp Designs
A seamless pattern formed from cross 4. To get the original tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Here's a dark background pattern that contains a steel grid pattern as a texture. Use it as a website background or for other purposes. It's free!
Source V. Hartikainen
This is a seamless pattern which is derived from a flower petal image.
Source Yamachem
Pattern that came out of playing with the 'slinky' plug-in for Paint.net
Source Firkin
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
The image depicts a seamless pattern which includes hexagonally-aligned gourds with BG in light-brown.
Source Yamachem
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
Prismatic Groovy Concentric Background No Black
Source GDJ
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
If you don’t like cream and pixels, you’re in the wrong place.
Source Mizanur Rahman
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Prismatic Geometric Pattern Background No Black
Source GDJ
Prismatic Geometric Pattern Variation 2 With Background
Source GDJ
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
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
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Background formed from the original with an emboss effect.
Source Firkin