This article aims to explain how to refresh the vst2, vst3, lv2, ladspa plugins on each daw available on linux. Up to now I add some of the possible DAW usable on Linux in the future I will add more on this article.
List of DAW/Software with scan plugins guide:
Ardour: go to Edit>Preferences and click on VST under Plugins, ensure that the ~/.vst path is present and after rescan for plugins (edit the path and after you close it, it ask you if you need to rescan or click on Plugins and click Scan for Plugins button)
Reaper: go to Options>Preferences and click on VST under Plugins and click Re-Scan button
Carla: Click on Add plugin, after clickon refresh and in the end click on Scan
Carla is not a DAW but i use it to add plugins with Jack without DAW, for example in Live or when I use particular programs like LMMS to include all external vst/lv2.
Ardour is my favorite DAW open source but sometimes it is not perfect, Reaper is my favourite DAW for now, and I use Carla when I do not want to start a DAW.
Enjoy your music and use Linux.