Your eyes can trip a bit from looking at this – use it wisely.
Source Michal Chovanec
Colorful Floral Background No Black
Source GDJ
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Number 1 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
A seamless pattern with wide vertical stripes colored in pale yellow.
Source V. Hartikainen
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Similar to original, but without gaps in between the arrows. This seamless pattern was created from a rectangular tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Neat little photography icon pattern.
Source Hossam Elbialy
Here's a subtle marble-like background for use on websites.
Source V. Hartikainen
From a drawing in 'Cassell's Library of English Literature', Henry Morley, 1883.
Source Firkin
A large (588x375px) sand-colored pattern for your ever-growing collection. Shrink at will.
Source Alex Tapein