Retro Circles Background 8 No Black@2X #438
 Dark  CC 0

Retro Circles Background 8 No Black

Source GDJ

 More Textures
Retro Circles Background 6@2X #429
 Noise  CC 0

Retro Circles Background 6

Source GDJ

Interlocking pattern 3 #2406
 Grid  CC 0

A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.

Source Firkin

Greek key pattern 5 #2294
 Dark  CC 0

Seamless pattern made from a tile that can be obtained in Inkscape by selecting the rectangle and using shift+alt+i.

Source Firkin

Tessellation 15 (colour 3) #2220
 Red  CC 0

The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.

Source Firkin

Fabric pattern 3 (colour 6) #2382
 Fabric  CC 0

Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.

Source Firkin

Batthern@2X #325
 Grid  CC BY-SA 3.0

Sometimes simple really is what you need, and this could fit you well.

Source Factorio.us Collective

Lined Paper #362
 Stripes  CC BY-SA 3.0

The classic notebook paper with horizontal stripes.

Source Are Sundnes

Prismatic Abstract Geometric Background 5 No Black #402
 Noise  CC 0

Prismatic Abstract Geometric Background 5 No Black

Source GDJ

Background pattern 19 (outline) #204
 Light  CC 0

A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.

Source Firkin

Vintage pattern #1959
 Grid  CC 0

Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.

Source Firkin

Black And White Floral Pattern Background Inverse #197
 Dark  CC 0

Black And White Floral Pattern Background from PDP.

Source GDJ