A couple of quick demos
For a more uniform texture like those boards / paper / concrete, first try the resynthesizer plugin. That is what it is made for.
For slightly more complicated patterns, try the GEGL tile seamless Filters -> Map -> Tile Seamless It is a little better than the old Gimp 2.8 version.
https://youtu.be/DEPR6TERboE two and a half minutes
More complicated, tends to be more hands on, but you can still use that Tile Seamless as a basis to build on.
For a more uniform texture like those boards / paper / concrete, first try the resynthesizer plugin. That is what it is made for.
For slightly more complicated patterns, try the GEGL tile seamless Filters -> Map -> Tile Seamless It is a little better than the old Gimp 2.8 version.
https://youtu.be/DEPR6TERboE two and a half minutes
More complicated, tends to be more hands on, but you can still use that Tile Seamless as a basis to build on.