For those who believe that Gimp does not have enough filters can now be downloaded G'MIC, a plugin for Gimp that has dozens of very interesting filters. You can download it from their website (also available is a. Deb for different versions of Ubuntu).

Once installed, open Gimp and you can find at the end of the Filters menu, called "G'MIC Toolbox". When you open it you find something like this

In this video you can see one of the possible applications in which this plugin can be very useful to us

To install this plugin execute the following commands from TERMINAL