A seamless pattern based on a rectangular tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
Prismatic Rounded Squares Grid 4 No Background
Source GDJ
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
Tile available in Inkscape using shift-alt-i on the selected rectangle
Source Firkin
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
Continuing the geometric trend, here is one more.
Source Mike Warner
A brown seamless wood texture in a form of stripe pattern. The result has turned out pretty well, in my opinion.
Source V. Hartikainen
Seamless Light Background Texture.
Source V. Hartikainen
A seamless pattern based on a rectangular tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
The tile this fill pattern is based on can be had by using shift+alt+i on the rectangle.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A seamless dark leather-like background texture with diagonal lines that look like stitches.
Source V. Hartikainen
A seamless pattern of dark bricks. Maybe it's not very realistic, but it looks good in my opinion.
Source V. Hartikainen
A free tileable background colored in off-white (antique white) color.
Source V. Hartikainen
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
This ladies and gentlemen, is texturetastic! Love it.
Source Adam Pickering
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
Prismatic Basic Pattern 2 No Background
Source GDJ