Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
A free background pattern with abstract green tiles.
Source V. Hartikainen
Prismatic Triangular Background Design Mark II 5
Source GDJ
Remixed from a JPG that was uploaded to Pixabay by theasad121
Source Firkin
ZeroCC tileable stone texture, edited from pixabay. CC0
Source Sojan Janso
More tactile goodness. This time in the form of some rough cloth.
Source Bartosz Kaszubowski
A free tileable background colored in off-white (antique white) color.
Source V. Hartikainen
A bit of scratched up grayness. Always good.
Source Dmitry
Adapted from an image that was uploaded to Pixabay by Anerma.
Source Firkin
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
Fix and cc0 to get the tile this is based on.
Source SliverKnight
Used a cherry by doctormo to make this seamless pattern
Source Firkin
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
A dark pattern made out of 3×3 circles and a 1px shadow. This works well as a carbon texture or background.
Source Atle Mo
Zero CC tileable wood texture, made by me procedurally in Neo Texture Edit.
Source Sojan Janso
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein