From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
Zero CC tileable hard cover green book, scanned and made by me. CC0
Source Sojan Janso
Inspired by a design found in 'Konstantinápolyi emlékeim', Miklos Chriszto, 1893.
Source Firkin
Prismatic Groovy Concentric Background 3
Source GDJ
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
This is the remix of "polka dot seamless pattern".The image depicts polka dot seamless pattern.
Source Yamachem
Love the style on this one, very fresh. Diagonal diamond pattern. Get it?
Source INS
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
Prismatic Snowflakes Pattern 2 No Background
Source GDJ
A lovely light gray pattern with stripes and a dash of noise.
Source V. Hartikainen
Prismatic Floral Pattern 3 Variation 3 No Background
Source GDJ
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Lovely pattern with splattered vintage speckles.
Source David Pomfret
A textured orange background pattern with vertical stripes.
Source V. Hartikainen
Sort of reminds me of those old house wallpapers.
Source Tish
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo