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 Curved Diamond Pattern 4 No Background
Source GDJ
The following repeating website background is colored in a blue gray color and resembles a concrete wall or something similar to it.
Source V. Hartikainen
This one is amazing, truly original. Go use it!
Source Viahorizon
This is sort of fresh, but still feels a bit old school.
Source Martuchox
A browner version of the original weathered fence texture.
Source Firkin
Inspired by a drawing in 'Poems', James Smith, 1881.
Source Firkin
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
Nicely executed tiling for an interesting pattern.
Source Ignasi Àvila Padró
Background formed from the original with an emboss effect
Source GDJ
Inspired by a 1930s wallpaper pattern I saw on TV.
Source Firkin
Prismatic Abstract Geometric Background 3
Source GDJ
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
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
The image depicts a seamless pattern which was made using stripe-like things including borders.I used OCAL cliparts called "Blue Greek Key With Lines Border" uploaded by "GR8DAN" and "daisy border" uploaded by "johnny_automatic".Thanks.
Source Yamachem
A beautiful dark wood pattern, superbly tiled.
Source Omar Alvarado
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
From a drawing in 'Picturesque New Guinea', J Lindt, 1887.
Source Firkin
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
From a drawing in 'Codogno e il suo territorio nella cronaca e nella storia'', Gio and Giarella Cairo, 1897.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso