Vichy@2X #72
 Light  CC BY-SA 3.0

This one could be the shirt of a golf player. Angled lines in different thicknesses.

Source Olivier Pineda

 More Textures
Prismatic Arrows Background 2 #393
 Light  CC 0

Prismatic Arrows Background 2

Source GDJ

Starring #585
 Dark  CC BY-SA 3.0

If you need stars, this is the one to get.

Source Agus Riyadi

Retro Squares Background #414
 Noise  CC 0

Retro Squares Background

Source GDJ

Colorful Floral Background 3 #483
 Dark  CC 0

Colorful Floral Background 3

Source GDJ

Background pattern 215 (colour 3) #2369
 Pink  CC 0

A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.

Source Firkin

Snowflake remix #155
 Dark  CC 0

A bit simplified version. Although it could be edited out to be simpler. Anyway, this time the tiling is converted to a pattern fill -which is using clipping for the tile's edges.

Source Lazur URH

Ribbon pattern 2 (version 2, colour 4) #2036
 Colorful  CC 0

The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.

Source Firkin

Retro Circles Background 7 No Black #433
 Unknow  CC 0

Retro Circles Background 7 No Black

Source GDJ

Prismatic Polka Dots Mark II 2 No Background #532
 Noise  CC 0

Prismatic Polka Dots Mark II 2 No Background

Source GDJ

Cross Stripes@2X #48
 Dark  CC BY-SA 3.0

Nice and simple crossed lines in dark gray tones.

Source Stefan Aleksić

Seamless Core Pattern 3 #167
 Dark  CC 0

Seamless Core Pattern 3

Source GDJ

Prismatic Curved Diamond Pattern 5 No Background #543
 Diamond  CC 0

Prismatic Curved Diamond Pattern 5 No Background

Source GDJ