Here I have tried to create something that would look like maple wood. Not sure how well it's turned out, but at least it looks like wood.
Source V. Hartikainen
Prismatic Abstract Geometric Background 4
Source GDJ
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Brushed aluminum, in a bright gray version. Lovely 2X as well.
Source Andre Schouten
A colourful background drawn originally in paint.net and vectorised in Vector Magic.
Source Firkin
Love me some light mesh on a Monday. Sharp.
Source Wilmotte Bastien
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Original minus the background
Source Firkin
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
A textured orange background pattern with vertical stripes.
Source V. Hartikainen
A rusty grunge background for websites. Feel free to use it in your site's theme.
Source V. Hartikainen
I love these crisp, tiny, super subtle patterns.
Source Badhon Ebrahim
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Less Black than we're painted', James Payn, 1884.
Source Firkin
Continuing the geometric trend, here is one more.
Source Mike Warner
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel