Grunge Wall #81
 Wall  CC BY-SA 3.0

Light gray grunge wall with a nice texture overlay.

Source Adam Anlauf

 More Textures
Background pattern 263 #2073
 Pink  CC 0

Actually remixed from a pattern on Pixabay. But then noticed a very similar one on Openclipart.org uploaded by btj51q2.

Source Firkin

"Polished Stone", Gray Background Pattern #1053
 Stone  CC BY-SA 3.0

A seamless gray background texture suitable for use on websites. To me, it has the look of stone. Feel free to modify it to meet your needs (by making it a bit lighter or darker, for example).

Source V. Hartikainen

Prismatic Dots Background@2X #502
 Noise  CC 0

Prismatic Dots Background

Source GDJ

Soft Wallpaper #95
 Wall  CC BY-SA 3.0

Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.

Source Atle Mo

Background pattern yellow #1999
 Yellow  CC 0

Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i

Source Firkin

Foggy Birds@2X #580
 Light  CC BY-SA 3.0

Hey, you never know when you’ll need a bird pattern, right?

Source Pete Fecteau

Concrete Wall 2@2X #80
 Wall  CC BY-SA 3.0

A light gray wall or floor (you decide) of concrete.

Source Atle Mo

crissXcross #111
 Dark  CC BY-SA 3.0

Dark pattern with some nice diagonal stitched lines crossing over.

Source Ashton

Grilled Noise #581
 Fabric  CC BY-SA 3.0

You could get a bit dizzy from this one, but it might come in handy.

Source Dertig Media

Rough Cloth@2X #313
 Fabric  CC BY-SA 3.0

More tactile goodness. This time in the form of some rough cloth.

Source Bartosz Kaszubowski

Retro Circles Background 5 No Black@2X #427
 Noise  CC 0

Retro Circles Background 5 No Black

Source GDJ

Mirrored Squares@2X #124
 Dark  CC BY-SA 3.0

Did some testing with Repper Pro tonight, and this gray mid-tone pattern came out.

Source Atle Mo