This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
Prismatic Geometric Pattern Background No Black
Source GDJ
Actually remixed from a pattern on Pixabay. But then noticed a very similar one on Openclipart.org uploaded by btj51q2.
Source Firkin
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Remixed from a JPG that was uploaded to Pixabay by susanlu4esm
Source Firkin
With a name like this, it has to be hot. Diagonal lines in light shades.
Source Isaac
If you don’t like cream and pixels, you’re in the wrong place.
Source Mizanur Rahman
Formed by distorting a JPG from PublicDomainPictures
Source Firkin
Prismatic Groovy Concentric Background
Source GDJ
Colored maple leaves scattered on a surface. This is tileable, so it can be used as a background or wallpaper.
Source Eady
A repeating background with dark brown stone-like texture and abstract pattern that looks like tree trunks.
Source V. Hartikainen
Prismatic Abstract Line Art Pattern Background
Source GDJ
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim