I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Remixed from a drawing in 'Canadian forest industries July-December', 1915
Source Firkin
Prismatic Isometric Cube Extra Pattern No Background
Source GDJ
A seamless pattern with wide vertical stripes colored in pale yellow.
Source V. Hartikainen
A seamless pattern drawn originally in Paint.net by distorting a slice of background pattern 116 and copying the resulting triangle numerous times.
Source Firkin
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
A blue background wallpaper for websites. It has a seamless texture with vertical stripes. It looks quite nice not only when using as a tiled background on websites, but also on computer desktops.
Source V. Hartikainen
Sharp pixel pattern, just like the good old days.
Source Paridhi
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
ZeroCC tileable stone texture, edited from pixabay. CC0
Source Sojan Janso
Background Wall, Art Abstract, Star Well & CC0 texture.
Source Ractapopulous
This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Prismatic Snowflakes Pattern 3 No Background
Source GDJ
A simple bump filter made upon request at irc #inkscape at freenode. Made a screen capture of the making here: https://youtu.be/TGAWYKVLxQw
Source Lazur URH
This makes me wanna shoot some pool! Sweet green pool table pattern.
Source Caveman
Zero CC tileable yellow craft paper; scanned and made by me. CC0
Source Sojan Janso
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
Black brick wall pattern. Brick your site up!
Source Alex Parker