I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
Prismatic Polka Dots Mark II No Background
Source GDJ
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
A seamless pattern formed from a modified version of rwwgub's tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Number 1 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
Kaleidoscope Prismatic Abstract No Background
Source GDJ
Snap! It’s a pattern, and it’s not grayscale! Of course you can always change the color in Photoshop.
Source Atle Mo
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Tiny little fibers making a soft and sweet look.
Source Badhon Ebrahim
So tiny, just 7 by 7 pixels – but still so sexy. Ah yes.
Source Dmitriy Prodchenko
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
This one has rusty dark brown texture.
Source V. Hartikainen
Zero CC tileable hard cover cells, skin like, book texture. 4K, Scanned and made by me CC0
Source Sojan Janso
This was submitted in a beige color, hence the name. Now it’s a gray paper pattern.
Source Konstantin Ivanov
Embossed lines and squares with subtle highlights.
Source Alex Parker
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
I have no idea what J Boo means by this name, but hey – it’s hot.
Source j Boo
Prismatic Abstract Line Art Pattern Background
Source GDJ