Prismatic Groovy Concentric Background 3 No Black
Source GDJ
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Free tiled background with colorful stripes and white splatter.
Source V. Hartikainen
Floral patterns might not be the hottest thing right now, but you never know when you need it!
Source Lauren
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A version without colours blended together to give a different look.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev