More Textures
Noisy #45
 Paper  CC BY-SA 3.0

Looks a bit like concrete with subtle specks spread around the pattern.

Source Mladjan Antic

Background pattern 1 #220
 Noise  CC 0

A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.

Source Firkin

Floral pattern 7 (colour 4) #2288
 Green  CC 0

Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.

Source Firkin

Background pattern 263 #2073
 Pink  CC 0

Actually remixed from a pattern on Pixabay. But then noticed a very similar one on Openclipart.org uploaded by btj51q2.

Source Firkin

Prismatic Isometric Cube Extra Pattern No Background #405
 Light  CC 0

Prismatic Isometric Cube Extra Pattern No Background

Source GDJ

Retro Circles Background 5 #424
 Noise  CC 0

Retro Circles Background 5

Source GDJ

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

Mosaic Gems Background@2X #527
 Noise  CC 0

Mosaic Gems Background

Source GDJ

Background pattern 269 #2062
 Dark  CC 0

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

Source Firkin

Background pattern 203 (colour 2) #2485
 Green  CC 0

A seamless pattern formed from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

Background pattern 262 #2075
 Dark  CC 0

Inspired by a pattern found in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.

Source Firkin

Small Crackle Bright@2X #353
 Light  CC BY-SA 3.0

Light gray pattern with an almost wall tile-like appearance.

Source Markus Tinner

Prismatic Dots Background 8 #515
 Noise  CC 0

Prismatic Dots Background 8

Source GDJ

Background pattern 202 #2491
 Brown  CC 0

Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.

Source Firkin