This could be a hippy vintage wallpaper.
Source Tileable Patterns
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Prismatic Snowflakes Pattern 2 No Background
Source GDJ
A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
One more in the line of patterns inspired by Japanese/Asian styles. Smooth.
Source Kim Ruddock
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
This one looks like a cork panel. Feel free to use it as a tiled background on your blog or website.
Source V. Hartikainen
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Not the Rebel alliance, but a dark textured pattern.
Source Hendrik Lammers
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
From a drawing in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin
ZeroCC tileable moss texture, photographed and made by me. CC0
Source Sojan Janso
A gray background pattern with a texture of textile. Suits perfectly for web design.
Source V. Hartikainen
A bit of scratched up grayness. Always good.
Source Dmitry
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
This is the remix of "Strawberry Pattern Background" uploaded by "GDJ". Thanks. I realigned strawberries so as to get seamless and changed the BG color.
Source Yamachem
A background tile of dark textile. Made this a long time ago and just now decided to publish it.
Source V. Hartikainen
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
Number 1 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Clover with background for St. Patrick's Day. Add to a card with a doily, ribbon, a leprechaun or other embellishments.
Source BAJ